Rapid-recall takeaways distilled from the PSA question bank, grouped by specialty. One pearl per high-frequency concept. Use it for last-pass revision alongside questions, not as a replacement for them.
625 pearls · 8 specialties · Generated 6 November 2026
Providing Information
80 high-yield facts
Amlodipine ankle swelling is common and dose-dependent - it is arteriolar, not fluid retention, and does not respond to diuretics but may improve with ACEi combination.
Glucagon for severe hypoglycaemia - IM injection when unconscious/unable to swallow, call 999, recovery position, and feed when conscious to prevent recurrence.
GTN - sit down, spray sublingual, repeat once after 5 minutes, then 999 if pain persists; never combine with PDE5 inhibitors due to fatal hypotension risk.
Insulin and driving - notify DVLA, glucose ≥5 before driving, check every 2 hours, carry glucose, and surrender licence after severe hypo requiring assistance.
Chloramphenicol eye drops = pull down lower lid, apply 1 drop, use for 48h after symptoms resolve, do NOT share, store in fridge, discard at 28 days.
Low-dose amitriptyline for pain - take early evening, expect drowsiness initially, start low and go slow, and it takes 2-4 weeks to work for neuropathic pain.
Darbepoetin = longer-acting (less frequent injections), same efficacy and precautions as epoetin, BP monitoring still needed, check iron stores.
PPI = take 30 minutes before food, review long-term need annually, risks include C. diff/hypomagnesaemia/fractures; taper when stopping.
the day; (2) Folic acid 5mg is taken on a different day (not the same day as methotrexate) to reduce side effects; (3) Regular blood monitoring (FBC, LFTs, U&E) is essential - typically every 2 weeks for first 6 weeks, then monthly; (4) Teratogenicity - effective contraception is mandatory; wait 3 months after stopping before conceiving (applies to BOTH sexes); (5) Report immediately: sore throat, fever, mouth ulcers, unexplained bruising/bleeding (bone marrow suppression), persistent cough/breathlessness (pneumonitis), jaundice; (6) Avoid live vaccines and excessive alcohol; (7) Drug interactions - trimethoprim and NSAIDs increase toxicity.
Mesalazine = continue even when well, adherence prevents relapse, stick to same brand, annual renal monitoring.
Anticoagulant alert card = carry ALWAYS, for ALL anticoagulants (not just warfarin), informs emergency care, supplement with verbal disclosure.
Prescribing
80 high-yield facts
Pregnancy analgesia = paracetamol is safest - avoid ALL NSAIDs, especially after 28 weeks (ductus arteriosus closure).
AECOPD with purulent sputum = amoxicillin 5 days + prednisolone 30mg for 5 days - short and sweet.
High refeeding risk = IV Pabrinex + correct electrolytes + start nutrition at 10kcal/kg/day - NEVER refeed aggressively.
Severe hyponatraemia + seizures = hypertonic saline urgently - max 10mmol/L correction in 24 hours to prevent osmotic demyelination.
Tacrolimus + CYP3A4 inhibitors (clarithromycin, azole antifungals, grapefruit) = toxic levels. Use azithromycin if macrolide needed.
First trimester hyperthyroidism = PTU (not carbimazole due to embryopathy). Switch to carbimazole after first trimester.
IV vancomycin for MRSA = check trough before 3rd/4th dose, target 15-20mg/L. Oral vancomycin = only for C. diff (not systemic).
Dabigatran for VTE = 5 days LMWH first, then 150mg BD. Requires LMWH lead-in (like edoxaban). Reversible with idarucizumab.
Bronchiolitis = supportive care ONLY - no bronchodilators, no steroids, no antibiotics. Admit if SpO2 <92% or poor feeding.
Dalteparin 5000 units SC OD = standard surgical thromboprophylaxis. Extended prophylaxis (28-35 days) for major orthopaedic surgery.
Iron deficiency anaemia = ferrous sulphate 200mg BD-TDS for 3 months after Hb normalises - always find and treat the cause.
IV potassium - max 40mmol/L peripherally, max 10mmol/hour. Higher concentrations need central access and monitoring.
Calculation Skills
80 high-yield facts
For drugs with linear pharmacokinetics, the dose-level relationship is proportional - double the dose, double the level. This does NOT apply to phenytoin.
Displacement volume matters most when preparing partial doses from a vial - always account for it in paediatric and neonatal prescribing to avoid dosing errors.
Heparin comes in different concentrations (1,000, 5,000, and 25,000 units/mL) - always verify which concentration is available before drawing up the dose.
AG = Na − (Cl + HCO3) - a raised anion gap indicates the presence of unmeasured anions (ketones, lactate, uraemic toxins, ingested poisons).
Total bolus = meal dose + correction dose - the correction factor determines how many units to add for glucose above target.
In obesity (BMI >35), increase enoxaparin prophylaxis from 40 mg OD to 40 mg BD - under-dosing in obese patients is a recognised cause of prophylaxis failure.
Neonatal drug doses require meticulous calculation - always double-check with a second practitioner and use appropriate syringes for small volumes.
Warfarin adjustments should be proportional (10-20%) - large dose changes risk overshooting the target range and increasing bleeding risk.
Never split capsules - always use the correct formulation or contact pharmacy to source the appropriate strength.
Rate = Volume ÷ Time - always slow the rate in heart failure, renal impairment, or elderly patients to prevent fluid overload.
Insensible losses increase by ~200 mL/day per °C of fever - always adjust fluid prescribing for temperature, respiratory rate, and other sources of loss.
Vitamin D loading is 50,000 IU weekly for 6 weeks (total 300,000 IU) - always follow up with maintenance therapy and recheck levels at 3 months.
Planning Management
80 high-yield facts
Resistant hypertension + K+ ≤4.5 = add spironolactone 25mg (PATHWAY-2 evidence); if K+ >4.5, use doxazosin or bisoprolol.
IBS first-line = antispasmodic (mebeverine); second-line = low-dose amitriptyline; avoid lactulose as it worsens bloating.
Add lamotrigine or levetiracetam as adjunctive therapy when focal epilepsy monotherapy fails per NICE NG217 - levetiracetam has no significant interactions and is well-suited as add-on to enzyme-inducing AEDs such as carbamazepine.
Standard DAPT after ACS + PCI = 12 months, then stop the P2Y12 inhibitor and continue aspirin lifelong (NICE NG185); shorter DAPT for HBR (ARC-HBR), longer DAPT for very high ischaemic risk (DAPT score); ticagrelor first-line post-ACS per PLATO.
SGLT2 inhibitors are preferred third-line in T2DM with CKD or albuminuria - they provide glycaemic control plus renal protection per NICE NG28 and DAPA-CKD/CREDENCE evidence.
Graves disease first-line = carbimazole + propranolol; PTU only in first trimester pregnancy or carbimazole intolerance.
Stop preventive medications in terminal illness when time-to-benefit exceeds prognosis - maintain symptom control drugs and communicate the rationale sensitively per NICE NG31.
Non-adherence → explore beliefs and concerns (concordance approach); don't increase doses or change drugs without first addressing adherence.
AKI = stop the 'triple whammy' (NSAID + ACEi + diuretic); ibuprofen is the most important drug to stop.
Oral morphine to SC diamorphine = divide by 3; oral morphine to SC morphine = divide by 2; always prescribe PRN breakthrough doses.
Step 3 hypertension adds a thiazide-like diuretic (indapamide preferred) to ACEi/ARB + CCB per NICE NG136 - spironolactone is reserved for step 4 resistant hypertension.
Data Interpretation
80 high-yield facts
Gentamicin trough must be <1 mg/L - if elevated, withhold and extend interval. Never give the next dose without checking the trough level.
FEV1/FVC <0.70 post-bronchodilator = COPD - smoking cessation is the only intervention that changes disease progression.
NNT = 1/ARR - lower NNT = more effective. Always consider NNT in the context of disease severity, treatment duration, and side effects (NNH).
Acute pulmonary oedema = sit up + O₂ + IV furosemide + IV GTN (if SBP >90) - morphine is no longer recommended.
A positive D-dimer does NOT confirm VTE - it must be combined with imaging (ultrasound for DVT, CTPA for PE) for definitive diagnosis.
Flucloxacillin can cause cholestatic jaundice up to 6 weeks after completing the course - always document this reaction to prevent re-exposure.
CK >10× ULN on a statin = stop immediately - rechallenge cautiously with a lower dose or alternative statin after CK normalises.
Always review culture results and change antibiotics if the organism is resistant to the current empirical therapy - targeted therapy improves outcomes and reduces resistance.
Bioequivalence = 90% CI of AUC and Cmax ratios within 80-125% - for NTI drugs, substitution should be done cautiously with TDM.
Primary prevention = atorvastatin 20 mg; secondary prevention = atorvastatin 80 mg - QRISK3 ≥10% is the threshold for treatment.
In digoxin toxicity, NEVER give IV calcium for hyperkalaemia - it causes fatal cardiac arrhythmias. Use DigiFab for severe toxicity.
QTc >500 ms = urgent drug review - stop the most easily substituted QT-prolonging drug first and correct electrolytes.
TCA overdose with QRS >120 ms = IV sodium bicarbonate - this is the definitive treatment for cardiac toxicity.
Adverse Drug Reactions
80 high-yield facts
Amiodarone pulmonary toxicity presents with progressive dyspnoea, reduced TLCO, and ground-glass opacities - perform baseline CXR and TFTs before starting.
Gentamicin ototoxicity is irreversible - monitor trough levels (<1 mg/L), avoid with loop diuretics when possible, and adjust dose for renal function.
Always start warfarin with concurrent heparin cover - skin necrosis occurs from transient protein C depletion, especially in protein C deficiency.
Non-selective beta-blockers are absolutely contraindicated in asthma - even cardioselective ones should be avoided; use CCBs or ACEi instead.
Andexanet alfa reverses factor Xa inhibitors; idarucizumab reverses dabigatran - vitamin K only works for warfarin.
Valproate must not be used in pregnancy - switch before conception; folic acid does NOT prevent valproate teratogenicity; the risk cannot be eliminated by dose reduction.
Monitor gentamicin troughs (<1 mg/L) and renal function regularly - nephrotoxicity from ATN is usually reversible if caught early; extend dosing intervals if troughs are elevated.
Monitor vancomycin troughs every 48-72 hours - levels >20 mg/L increase nephrotoxicity; AUC/MIC dosing is increasingly preferred over trough-only monitoring.
Check LFTs before starting isoniazid - stop if ALT >3x ULN with symptoms; risk increases with age, alcohol, and slow acetylator status.
Clindamycin has the highest C. difficile risk - use only when no alternatives exist; treat C. difficile with oral vancomycin (first-line per NICE); never give loperamide.
Nebulised ipratropium causes urinary retention in men with BPH - use salbutamol alone if possible; always assess anticholinergic burden in elderly patients.
Tacrolimus nephrotoxicity presents with rising creatinine, tremor, and hyperkalaemia - monitor trough levels closely and check for CYP3A4 drug interactions.
Drug Monitoring
80 high-yield facts
Patients on sedating medications have a legal duty to assess fitness to drive - codeine and gabapentin both impair driving; Group 2 licence holders have stricter standards; document driving advice in medical records.
Check INR daily during warfarin initiation (days 2-4 onwards) - concurrent anticoagulation must continue for at least 5 days and until INR is therapeutic on 2 consecutive checks.
G-CSF - monitor FBC for neutrophil recovery, watch for bone pain (common) and splenic rupture (rare); give 24-72h after chemotherapy; indicated for regimens with ≥20% febrile neutropenia risk.
Monitor HIV viral load every 3-6 months on stable ART - suppression (<50 copies/mL) is the treatment goal; investigate if viral load >200 on 2 consecutive samples.
Daily clinical pharmacist review of drug charts is best practice - reduces prescribing errors by 50-80%; includes reconciliation, interaction screening, allergy checking, and renal dosing; 7-day services are the gold standard.
Use non-calcium phosphate binders when calcium is elevated in CKD - avoid aluminium long-term; dietary restriction and dialysis adequacy also contribute; target phosphate 1.1-1.7 mmol/L.
Check HbA1c every 3-6 months in T2DM - less frequent if stable at target; HbA1c reflects 2-3 months of glucose; individualise targets based on treatment and patient factors.
Black triangle (▼) = intensive monitoring - report ALL suspected ADRs; it does not mean the drug is dangerous or restricted; helps detect rare ADRs not found in clinical trials.
Always test TPMT before starting azathioprine - intermediate activity requires 50% dose reduction; absent activity is a contraindication; FBC monitoring is still needed regardless of TPMT status.
Review doxazosin, benzodiazepines, and opioids as priority in fallers - postural hypotension is a key modifiable risk factor; multifactorial falls assessment includes medication review, physiotherapy, and vision.
Prescription Review
65 high-yield facts
Every prescription MUST be signed - unsigned prescriptions are not legally valid. Nurses should not administer from unsigned charts.
Phenytoin = zero-order kinetics - small dose increase, big level rise. Only increase by 25-50mg at a time and recheck levels.
C. difficile = ORAL vancomycin 125mg QDS. IV vancomycin does NOT reach the gut. Route is critical for this specific indication.
Vancomycin red man syndrome = rate-dependent, NOT allergy. Slow the infusion to max 10mg/min. Do NOT stop vancomycin permanently.
Paracetamol in adults <50kg = reduce dose to 15mg/kg per dose (max 60mg/kg/day) - standard 1g QDS can cause hepatotoxicity.
BMI >=35 = UKMEC 3 for COC (relative contraindication, risks generally outweigh benefits). Prefer progestogen-only methods or the copper IUD, because VTE risk increases with BMI.
Metformin + IV contrast (eGFR <60) = withhold metformin, restart 48 hours after contrast when renal function confirmed stable.
Migraine WITH AURA = absolute contraindication to COC (UKMEC 4) - increased stroke risk. Switch to progestogen-only method.
Never give oral medication during an active seizure (aspiration risk and unreliable absorption); buccal midazolam first-line, rectal diazepam alternative; review emergency care plans for transcription accuracy (NICE NG217, BNFc).
Methotrexate + trimethoprim = NEVER prescribe together - dual folate antagonism causes fatal bone marrow failure.
ACEi + K-sparing diuretic + NSAID = 'triple whammy' - AKI and hyperkalaemia. NEVER add NSAIDs to this combination.
Lithium + NSAID = lithium toxicity (reduced renal clearance). Also avoid ACEi, ARBs, and thiazides. Use paracetamol for pain instead.
Self-monitoring - fasting target 4-7, post-meal <8.5, test more when unwell or on sulfonylureas (hypo risk), and record results with context for clinical review per NICE NG28.
Diabetic feet = check daily, wear proper shoes, lukewarm water, never hot water bottles, urgent care for any wound.
Alendronic acid = empty stomach, full glass of water, sit upright 30 minutes, same day weekly, separate from levothyroxine.
Loperamide - effective for IBS-D, lowest effective dose, maximum 16mg/day, cardiac risk at excessive doses, and use alongside dietary management.
Allopurinol = may worsen gout initially (take colchicine cover ≥6 months), take daily long-term, do NOT stop during flares, does NOT treat acute attacks.
Topical steroids = use FTU guide, never use potent on face/flexures, apply thinly, use for limited courses with breaks.
Insulin counselling covers injection technique, hypo recognition and treatment, glucose monitoring, DVLA notification, and correct storage - hypos are the key safety concern.
Never stop beta-blockers abruptly - taper gradually, report breathlessness especially with asthma, and expect reduced exercise heart rate and possible fatigue.
Insulin pen = new needle, prime, inject SC, count to 10, rotate sites, sharps disposal.
Opioid counselling = co-prescribe laxatives from day 1, warn about drowsiness/driving, do not escalate dose without advice, safe storage.
Check inhaler technique at every review - spacers improve MDI drug delivery, reduce side effects, and correct technique is the single most important factor in inhaler effectiveness.
Lamotrigine = report ANY rash immediately (SJS/TEN risk); slow titration is mandatory; safer in pregnancy than valproate.
Mesalazine must continue during remission - it halves relapse risk and protects against colorectal cancer, brands are not interchangeable, and alternative formulations improve adherence.
Gabapentin = titrate gradually, expect initial drowsiness, NEVER stop suddenly, now a Schedule 3 controlled drug.
Antibiotic counselling = complete the full course as prescribed, take at regular intervals, report rash or allergic symptoms, seek review if no improvement in 48 hours.
Trimethoprim = folate antagonist (avoid in pregnancy), 3-day course for UTI, risk of hyperkalaemia (especially with ACEi/ARBs), avoid with methotrexate.
Diazepam = short-term only (2-4 weeks max), causes drowsiness and dependence, do NOT drive while impaired, avoid alcohol, never stop suddenly.
Diazepam - short-term only (max 2-4 weeks), no driving if impaired, no alcohol, and rapid dependence risk per NICE guidance.
Doxycycline - avoid sun, take upright with water, don't lie down for 30 minutes, separate from dairy and iron, and avoid in pregnancy.
Clozapine - mandatory blood monitoring for agranulocytosis, registered prescribing service, report sore throat/fever immediately, and never stop abruptly.
DOAC counselling = adherence is paramount (short half-life), no INR needed, but annual renal monitoring required; report bleeding signs.
Azathioprine = regular blood monitoring, report infections/bleeding immediately, never combine with allopurinol at full dose, sun protection.
Paracetamol max 4g/day, check cold remedies for hidden paracetamol, overdose is a medical emergency requiring immediate treatment.
Levothyroxine = empty stomach, 30 min before food, separate from iron/calcium by 4 hours; these interactions commonly cause apparent treatment failure.
Salbutamol overuse (≥3x/week or ≥3 inhalers/year) = red flag for poor asthma control; review preventer therapy, technique, and adherence.
Isotretinoin = two forms of contraception (PPP), monthly pregnancy tests, monitor lipids/LFTs, report mood changes, expect dry skin/lips.
Calcium = take with food, separate from alendronate and levothyroxine by 2-4 hours, split doses for better absorption, do not exceed 1500mg daily.
Spironolactone - monitor potassium and renal function (1 week, 4 weeks, then regularly); risk of hyperkalaemia is amplified by ACE inhibitors and renal impairment; gynaecomastia is common, eplerenone is an alternative.
ORS = exact water volume stated, give small frequent sips (not bolus), do NOT add to juice or milk, discard after 1 hour, seek help if unable to tolerate.
Steroid card = carry ALWAYS, enables emergency adrenal crisis treatment, double dose when ill, seek IM hydrocortisone if vomiting.
Fondaparinux = once-daily SC, no routine monitoring, no HIT risk (unlike heparin), renal dose adjustment needed, no specific reversal agent.
Methotrexate affects BOTH male and female fertility - men should stop at least 3 months before trying to conceive; teratogenic to fetus; use contraception during treatment.
Ciclosporin = avoid grapefruit (CYP3A4), regular BP and renal monitoring, infection/skin cancer risk, extensive drug interactions.
Chemo patient + temperature ≥38°C = attend A&E immediately and say you're on chemotherapy; neutropenic sepsis is life-threatening.
Radiotherapy skin = non-perfumed moisturiser, gentle washing, avoid sun and irritants, no adhesives, loose clothing, report broken skin.
Domperidone = lowest dose, shortest time (max 1 week), cardiac arrhythmia risk (QT prolongation), MHRA restrictions, ECG recommended before prescribing.
Loperamide = AVOID in acute UC colitis (toxic megacolon risk), treat the underlying flare instead, only consider cautiously in quiescent disease.
Cinacalcet = lowers PTH (calcimimetic), risk of hypocalcaemia (monitor calcium regularly), take with food, nausea common, continue other CKD-MBD treatments.
IV iron anaphylaxis = risk is real but very low, resuscitation available, stay 30 min for observation, report symptoms during infusion, benefits outweigh risks.
Sulfonylurea drivers - know the hypo rules ('5 to drive'), carry glucose, check before driving (DVLA Assessing fitness to drive). DVLA notification is mandatory for insulin-treated Group 1 and for ALL Group 2 diabetes.
Sick day rules = NEVER stop insulin, monitor glucose and ketones 2-4 hourly, maintain fluids, ketones >3.0 = A&E immediately.
Flash monitor = scan to read (no automatic alarms on basic), 14-day sensor, scan every 8 hours, fingerprick still sometimes needed, factory-calibrated.
Hypo = 15-20g fast glucose → recheck 15 min → long-acting carb; always carry glucose; 4 is the floor.
Glucagon = unconscious hypo, 1mg IM outer thigh, recovery position, call 999, oral glucose when conscious.
DKA prevention = NEVER stop insulin, check ketones if glucose >14, can develop in hours, sick day rules essential.
Travel = hand luggage, medical letter, adjust basal for time zones, extra supplies, frequent monitoring.
Metoclopramide = max 5 days (MHRA), risk of acute dystonia/EPS (treat with procyclidine), avoid in Parkinson's, avoid long-term use (tardive dyskinesia).
Naloxone = recognise OD (unresponsive + slow breathing), inject IM outer thigh, call 999 ALWAYS, naloxone wears off so re-overdose possible.
EpiPen = use immediately for anaphylaxis, inject outer thigh 10 seconds, always carry TWO, call 999, check expiry.
Compression stockings = wear during the day (off at night), correct fitting essential, check ABPI first, check skin daily, replace every 3-6 months.
Mycophenolate = HIGHLY teratogenic (pregnancy prevention programme), TWO forms of contraception required, stop 6 weeks before conception, switch to azathioprine.
Rituximab = pre-medication before infusions, report ALL infections, avoid live vaccines, monitor immunoglobulins, continue methotrexate.
Adalimumab = SC injection abdomen/thigh, rotate sites, store in fridge, inject every 2 weeks, report infections.
Opioid-induced constipation = senna at night + Movicol dissolved in water daily; combination therapy is standard; maintain fluid intake.
Ondansetron - expect constipation (increase laxatives proactively), headache is common, and be aware of QT prolongation risk with high doses or concurrent QT-prolonging drugs.
HbA1c = average glucose over 3 months; above target means control needs improving; lifestyle and medication both contribute.
Warfarin requires INR monitoring, consistent vitamin K intake, interaction awareness, and immediate reporting of bleeding - always carry the yellow anticoagulant booklet.
Insulin = fridge for unused, room temp for in-use (max 28 days), NEVER freeze, protect from heat, carry in hand luggage.
Lithium needs regular level monitoring - maintain hydration, avoid NSAIDs and dehydration, and recognise toxicity signs urgently (tremor, vomiting, confusion).
Aspirin plus anticoagulant doubles bleeding risk - co-prescribe PPI, report bleeding signs, and minimise the duration of combination therapy.
Levothyroxine on an empty stomach - separate from iron and calcium by 4 hours, avoid coffee for 30 minutes, and maintain consistent brand for reliable absorption.
Rinse mouth and spit after every ICS dose - use a spacer with MDIs to reduce thrush risk, and ICS must be taken regularly as a preventer even when well.
One missed COC pill - take immediately and continue, no extra precautions needed in week 2. Two+ missed pills require condoms for 7 days and possible emergency contraception per FSRH.
Digoxin - check pulse before taking, recognise toxicity (nausea, visual changes, arrhythmias), maintain potassium >4.0mmol/L, and regular level monitoring is essential with narrow therapeutic index.
Uncomplicated vaginal candidiasis = fluconazole 150mg single dose - metronidazole is for BV, not thrush.
Emergency contraception within 72 hours = levonorgestrel 1.5mg single dose - copper IUD is the most effective method if acceptable.
Refractory hypokalaemia? Check and correct magnesium FIRST - Mg is essential for K⁺ channels in the kidney.
Moderate acne = topical retinoid (adapalene) + benzoyl peroxide - never use topical steroids on acne.
Acute gout with NSAID contraindications = colchicine 500mcg BD - never start allopurinol during an acute attack.
Gonorrhoea = ceftriaxone 1g IM single dose - always send sensitivities and perform test of cure at 2 weeks.
Graves' first-line = carbimazole - warn about agranulocytosis (sore throat/fever = urgent FBC). PTU is reserved for pregnancy.
GDM first-line drug = metformin - add insulin if targets not met. SGLT2i and DPP-4i are NOT safe in pregnancy.
Medical miscarriage = mifepristone 200mg then misoprostol 800mcg (24-48h later) - mifepristone primes the uterus for misoprostol.
Eclamptic seizure = magnesium sulphate 4g IV (NOT lorazepam or phenytoin) - it is also given prophylactically in severe pre-eclampsia.
Lithium = start low, check levels at 5-7 days (12hr post-dose), target 0.6-0.8mmol/L. Monitor renal and thyroid 6-monthly.
Neonatal resuscitation drug = adrenaline 20mcg/kg IV (0.2mL/kg of 1:10,000) per RCUK 2021 - ventilation remains the priority.
Allergic rhinitis with persistent congestion = intranasal steroid (fluticasone/beclometasone) - never use decongestant sprays long-term.
Ivabradine = If channel blocker for HFrEF - reduces HR without lowering BP. Sinus rhythm only, HR >=70, on max beta-blocker.
AOM in children >2 years = pain relief + delayed prescription - immediate antibiotics only if systemically unwell or bilateral in <2 years.
Match steroid potency to severity - betamethasone valerate 0.1% is a potent (not moderate) steroid, appropriate as a short flare-control course in significant lichenified eczema, alongside generous emollients, then step down.
Plaque psoriasis first-line = vitamin D analogue (calcipotriol) - combined with potent steroid if needed.
Shingles aciclovir dose = 800mg 5× daily for 7 days - not 200mg, which is for herpes simplex. Start within 72 hours.
Post-caesarean VTE prophylaxis = enoxaparin 40mg SC OD for 10 days minimum - assess for extended prophylaxis if high risk.
Hyperemesis gravidarum first-line antiemetic = cyclizine or promethazine - longest safety record in pregnancy.
In women of childbearing potential with generalised epilepsy, switch valproate to levetiracetam (or lamotrigine) before conception under specialist care - valproate carries ~10% major malformation risk and requires the Pregnancy Prevention Programme.
Suspected transfusion reaction = STOP the transfusion immediately - never slow it or continue, especially with haemodynamic instability.
Preterm labour tocolysis = nifedipine first-line - delays delivery 48h for steroids. MgSO₄ is for neuroprotection, not tocolysis.
ACEi cough? Switch to ARB - same pathway, no bradykinin accumulation.
Paracetamol overdose above treatment line = NAC infusion immediately - normal ALT at presentation does NOT mean safe.
Bacterial conjunctivitis = chloramphenicol 0.5% drops first-line - never use steroid drops without ophthalmology input.
Medical inpatients at VTE risk = enoxaparin 40mg SC OD - assess all admissions for VTE risk.
RhD-negative mother = anti-D at 28 weeks + after delivery if baby is RhD-positive - must be given in EVERY pregnancy.
Short-term insomnia = zopiclone for 2-4 weeks maximum - always the lowest dose, shortest duration.
Bisphosphonate therapy = always co-prescribe calcium + vitamin D - take 2 hours apart from the bisphosphonate.
Uncomplicated UTI in women = nitrofurantoin MR 100mg BD for 3 days first-line.
Acute severe asthma = oxygen-driven nebulised salbutamol + oral prednisolone 40mg - do not delay steroids.
Suspected meningitis = IV ceftriaxone 2g IMMEDIATELY - never delay antibiotics for investigations.
Orthopaedic prophylaxis = cefuroxime at induction - vancomycin only if MRSA positive or beta-lactam allergic.
Sick day rules = double the steroid dose during febrile illness - never stop replacement steroids.
RA flare = short-course prednisolone (5-7 days) as a bridge - do not change DMARDs without rheumatology input.
Depression first-line = SSRI (sertraline or fluoxetine) - start at standard dose, review in 2 weeks, continue 6 months after recovery.
Rapid tranquillisation = IM haloperidol + IM promethazine - never combine IM olanzapine with IM benzodiazepines.
Anaphylaxis = IM adrenaline 500mcg (1:1000) FIRST - never give 1:1000 IV, which is lethal.
H. pylori first-line = PPI + amoxicillin + clarithromycin for 7 days - confirm eradication with urea breath test at 4 weeks.
B12 deficiency + neuro features = IM hydroxocobalamin alternate days, then every 2 MONTHS. Without neuro = every 3 months.
AED use + pregnancy = high-dose folic acid (5mg) - start BEFORE conception, continue to 12 weeks.
Paediatric paracetamol comes in two strengths - 120 mg/5 mL (for younger children) and 250 mg/5 mL (for older children) - always check which formulation you are using.
Nitrogen balance = intake − (UUN + 4) - aim for positive balance during recovery; neutral balance (zero) means neither gaining nor losing lean body mass.
Always check weight before prescribing paracetamol - patients under 50 kg need dose reduction to prevent hepatotoxicity.
Digoxin loading is given in divided doses - never the full loading dose at once - and always monitor potassium, as hypokalaemia potentiates digoxin toxicity.
Aminophylline maintenance rate is 0.5 mg/kg/hr - reduce in heart failure, liver disease, and elderly patients; increase in smokers.
Methadone conversion is non-linear and complex - the ratio INCREASES with higher morphine doses. This switch should only be done by palliative care specialists.
Codeine to morphine is 10:1 - ten times the codeine dose gives the morphine equivalent. This is the most common step 2→3 opioid switch.
Oxytocin infusion starts low and is titrated slowly - continuous CTG monitoring is mandatory to detect uterine tachysystole.
Osmolal gap >10 suggests toxic alcohol ingestion - combined with raised AG acidosis, this strongly suggests methanol or ethylene glycol poisoning requiring urgent treatment.
Displacement volume is already accounted for in the manufacturer's reconstitution instructions - add the specified water volume to achieve the stated concentration.
For Michaelis-Menten drugs, Css = (Km × Dose) ÷ (Vmax − Dose) - levels rise steeply as dose approaches Vmax.
Each unit of packed red cells raises Hb by approximately 10 g/L - use a restrictive threshold of 70 g/L and aim for 70-90 g/L.
Treatment-dose enoxaparin is 1.5 mg/kg OD or 1 mg/kg BD - the prophylactic dose (40 mg OD) is very different and must not be confused.
Gentamicin is dosed on ideal body weight - using actual weight in obese patients leads to overdosing and increased toxicity risk.
Cockcroft-Gault is the gold standard for drug dose adjustment - use 1.04 for females, 1.23 for males.
Preterm fluid requirements increase incrementally - 60/90/120/150 mL/kg/day over the first 4 days, adjusted by weight changes and sodium levels.
Mass = mmol × MW ÷ 1000, so 40 mmol KCl = 2.98 g; use pre-mixed potassium bags and never infuse faster than 10 mmol/hour peripherally (BNF).
PCA maximum dose/hr = demand dose × (60 ÷ lockout) - but also check the 4-hour rolling maximum to prevent cumulative overdosing.
Caloric values: CHO = 4 kcal/g, protein = 4 kcal/g, fat = 9 kcal/g - '4-4-9' is a key nutritional calculation for TPN prescribing.
The '10 in 24' rule - never correct sodium by more than 10 mmol/L in 24 hours to prevent osmotic demyelination syndrome.
Metformin - review the dose at eGFR <45 and stop it at eGFR <30 to avoid lactic acidosis (BNF; NICE NG28).
For CVVH, use the Renal Drug Handbook - meropenem 1 g every 12 hours is standard, giving 2 g/day total.
Basal insulin titration is done gradually (2 units every 3 days) based on fasting glucose - never make large adjustments as this risks nocturnal hypoglycaemia.
Convert fentanyl patch → morphine equivalent → target opioid - always use the two-step conversion via morphine as the reference standard.
Displacement volume = volume the powder occupies - it matters most when drawing up partial doses from reconstituted vials.
Protein requirement = 1.3 g/kg/day for ICU patients - convert to nitrogen by dividing by 6.25.
Phenytoin loading is 20 mg/kg at max 50 mg/min with cardiac monitoring - always dilute in 0.9% NaCl, never dextrose.
Paediatric septic shock resuscitation uses 20 mL/kg boluses of 0.9% NaCl - reassess and repeat up to 3 times, then consider inotropes.
Convert the prescribed mg/kg dose to total mg first, then divide by the suspension concentration in mg/mL to obtain the volume - here 350 mg at 50 mg/mL gives 7 mL.
ESA target Hb is 100-120 g/L in CKD (NICE NG8) - make gradual 25% dose adjustments with monitoring every 2-4 weeks.
HCO3 deficit = 0.3 × weight × (target − actual) - only partially correct (to HCO3 15) and infuse slowly to avoid overcorrection.
NICE maintenance fluid formula is 25-30 mL/kg/day - this is a core calculation that forms the basis of safe post-operative fluid management.
Always verify the morphine solution concentration - Oramorph comes in 10 mg/5 mL and 100 mg/5 mL formulations, and confusion between these is a common prescribing error.
Paediatric hydrocortisone dose is 4 mg/kg (max 100 mg) - oral prednisolone is preferred if the child can swallow, as it is equally effective.
ABW = IBW + 0.4 × (actual − IBW) - the 0.4 factor represents the 40% distribution of hydrophilic drugs into excess adipose tissue.
For liquid formulations, use Volume = Dose (mg) ÷ Concentration (mg/mL) - always verify the correct suspension strength.
When a dose is given as mg/kg/day in divided doses, divide the total daily dose by the number of doses per day to get the single dose.
Oral oxycodone is twice as potent as oral morphine - divide the morphine dose by 2 to get the oxycodone equivalent.
When patients can no longer swallow, divide the total daily oral morphine dose by 2 (or 3 for diamorphine) for the SC equivalent.
Noradrenaline is first-line for septic shock - target MAP ≥65 mmHg and always administer via a central venous catheter.
The universal infusion formula is Rate = (Dose × Weight × 60) ÷ Concentration - memorise this for any mcg/kg/min to mL/hr conversion.
Drops/min = (Volume × drop factor) ÷ (Time in min) - know the three drop factors: 20 (standard), 15 (blood), 60 (micro/paediatric).
IV lorazepam 0.1 mg/kg (max 4 mg) is first-line in-hospital treatment for status epilepticus - can repeat once after 10 minutes.
Paediatric transfusion is 10-15 mL/kg - unlike adults, children receive calculated volumes rather than whole units.
Lithium therapeutic range is 0.4-1.0 mmol/L - always check the 12-hour trough level and monitor U&E, TFTs, and calcium.
Css = Rate ÷ CL - a simple but powerful equation for any constant-rate infusion at steady state.
NSAIDs in children require careful weight-based dosing - never exceed 30 mg/kg/day for ibuprofen, and always check for contraindications including asthma and dehydration.
Platelets are transfused over 30 minutes - much faster than packed red cells - and the transfusion trigger varies by clinical context.
A-a gradient = PAO2 - PaO2; calculate PAO2 with the alveolar gas equation and always apply the PaCO2/0.8 correction - a raised gradient with hypoxia and low PaCO2 points to PE or V/Q mismatch (NICE NG158 on suspected venous thromboembolism).
In hypoalbuminaemia a low total phenytoin level can be misleading - always correct for albumin (or measure the free level) before adjusting the dose.
CL = Rate in ÷ Css at steady state - this is the most fundamental pharmacokinetic relationship and is the basis for maintenance dose calculations.
Each 1 mmol/L drop in serum K+ ≈ 200 mmol total body deficit - hypokalaemia correction requires substantial replacement over time, not a single infusion.
AF = 1/(1 − e^(−0.693×τ/t½)) - when τ = t½, AF = 2 and steady-state levels are double the first-dose levels.
the trapezoidal rule sums (C1 + C2)/2 x delta-t across each interval - here 10 + 18 + 12 = 40 mg.h/L.
In renal impairment, drugs may require dose reduction OR interval extension - always check which approach the BNF recommends for each specific drug.
Loading dose = Target concentration × Volume of distribution - this fundamental PK equation appears frequently in the PSA.
Maintenance dose rate = Css × CL - if clearance decreases (renal/hepatic impairment), the maintenance dose must be reduced proportionally.
IBW (male) = 50 + 2.3(inches − 60); IBW (female) = 45.5 + 2.3(inches − 60) - used for aminoglycoside dosing and ventilator settings.
When converting from VRII to SC, use 80% of the 24h total, split 50:50 between basal and bolus - overlap SC with VRII for 30-60 minutes.
Percentage solutions for local anaesthetics - 0.125% = 1.25 mg/mL, 0.25% = 2.5 mg/mL, 0.5% = 5 mg/mL.
Always include insensible losses in fluid balance calculations - they are often forgotten, leading to underestimation of fluid deficit.
For syringe drivers, always calculate the SC-equivalent dose first, then determine the volume of injectable drug needed - the remainder is made up with water for injection.
In heart failure, transfuse slowly (3-4 hours per unit) with furosemide between units - each unit must be completed within 4 hours maximum.
Always run a substrate (dextrose) alongside a VRII - insulin without glucose substrate causes dangerous hypoglycaemia.
UFH dosing is weight-based and monitored by APTT - always double-check the syringe concentration before setting the pump rate.
NEVER give an aminophylline loading dose to a patient already on oral theophylline without checking a level first - this is a classic prescribing safety question.
When adding amiodarone to warfarin, reduce the warfarin dose by 30-50% empirically and monitor INR closely - the interaction is clinically significant and prolonged.
The conversion ratios differ by route - oral:SC is 2:1, oral:IV is 3:1 - confusing these is a common and dangerous prescribing error.
Start PN when the gut is non-functional and nutrition is needed - screen for refeeding risk, start slowly, and give thiamine before initiation per NICE CG32.
Transfuse cautiously in heart failure - one unit at a time with furosemide cover, and monitor for TACO, the most common serious transfusion complication per BSH guidelines.
In multimorbidity, prioritise symptom-relieving and mortality-reducing drugs - deprescribe preventive medications with long time-to-benefit in frail patients per NICE NG56.
Mechanical valve patients require bridging LMWH perioperatively - stop warfarin five days before, bridge with therapeutic LMWH, and restart warfarin post-operatively when safe.
Maximise statin dose before adding ezetimibe - atorvastatin 80mg is recommended for secondary prevention, and PCSK9 inhibitors are third-line per NICE CG181.
IVOS when afebrile 24-48h + tolerating oral + improving → switch to narrowest oral agent guided by sensitivities.
Standard TB treatment is 2 months RIPE then 4 months RI - co-prescribe pyridoxine, monitor LFTs and visual acuity, and notify public health per NICE NG33.
Start slowly (10kcal/kg/day) and give thiamine before refeeding in high-risk patients - hypophosphataemia is the hallmark of refeeding syndrome, and rapid feeding can be fatal per NICE CG32.
Start ESAs when Hb <100 g/L in CKD; target 100-120 g/L; ensure iron sufficiency (ferritin >200, TSAT >20%); monitor BP; per NICE NG203.
ADHD with inadequate coverage on IR methylphenidate → switch to modified-release for smoother symptom control.
Stop clopidogrel 7 days pre-surgery (after cardiac clearance), hold metformin on surgery day, and continue statins - perioperative medication review requires MDT communication.
Paediatric mild-moderate dehydration → ORS orally; IV fluids only for severe dehydration or ORT failure; avoid sugary drinks.
UTI in pregnancy = 7 days treatment; cefalexin is safe throughout; avoid trimethoprim in T1, nitrofurantoin at term, fluoroquinolones and tetracyclines always.
COPD with frequent exacerbations and raised eosinophils → escalate to triple therapy (LAMA+LABA+ICS).
COPD without asthmatic features + low eosinophils → start LAMA (tiotropium) as first-line maintenance.
T2DM + established CVD → consider GLP-1 RA (semaglutide/liraglutide) for proven cardiovascular benefit and weight loss.
TSH elevated on levothyroxine → increase dose by 25mcg and recheck TSH at 6-8 weeks; always check adherence and interactions.
Treatment-resistant depression → lithium augmentation under specialist care; monitor levels, renal, and thyroid function.
OCD needs higher SSRI doses than depression - fluoxetine up to 60-80mg; always optimise dose before switching.
OA knee pain escalation - try a topical then an oral NSAID with PPI cover before opioids; NICE NG226 advises against routine opioid use because they offer limited benefit and significant harm in chronic OA.
Optimise methotrexate dose (up to 25mg weekly) before adding or switching DMARDs in RA.
Moderate UC flare failing 5-ASA → oral prednisolone 40mg daily; azathioprine is for maintenance, not acute induction.
Recurrent UTI prophylaxis = nitrofurantoin 50-100mg at night for 3-6 months; review and consider stopping after 6 months.
For focal seizures uncontrolled on carbamazepine, add levetiracetam (broad spectrum, few interactions) per NICE NG217; ethosuximide is for absences only, and ongoing seizures bar Group 1 driving.
DAPT after ACS + stenting = 12 months; then stop P2Y12 inhibitor and continue aspirin 75mg lifelong.
Moderate acne after benzoyl peroxide failure → topical retinoid + topical antibiotic combination for 12 weeks.
Dukes C (node-positive) colon cancer → adjuvant FOLFOX/CAPOX for 3-6 months; DPD testing is mandatory before starting.
Persistent steatorrhoea on PERT → increase Creon dose (up to 100,000 units/meal) and add/increase PPI; ensure correct administration.
Short bowel + high-output stoma + failure to thrive on oral diet → home parenteral nutrition per BAPEN/NICE CG32; avoid hypotonic fluids as they worsen output; consider teduglutide (NICE TA804) to reduce PN dependency.
Stroke with dysphagia → NG feeding within 24-48 hours; consider PEG only if NG feeding needed >4 weeks (FOOD trial evidence).
Refeeding prevention = correct electrolytes + IV thiamine BEFORE feeding; start at 5-10 kcal/kg/day; monitor electrolytes 12-hourly.
Oral iron intolerance → try alternative preparation (fumarate/gluconate) or alternate-day dosing before IV iron.
Pernicious anaemia + neurological involvement → IM hydroxocobalamin alternate days then every 2 MONTHS (not 3); never give folate alone.
CKD anaemia with Hb <100 after iron optimisation → start ESA (darbepoetin/epoetin); target Hb 100-120; avoid over-correction.
Culture-guided de-escalation = switch to the narrowest effective antibiotic; IV-to-oral switch when clinically improving and tolerating oral.
Invasive aspergillosis first-line = IV voriconazole; fluconazole does NOT cover Aspergillus; check trough levels.
TB treatment = 2 months RIPE (intensive) + 4 months RI (continuation); total 6 months for drug-sensitive pulmonary TB.
HIV ART first-line = 2 NRTIs + integrase inhibitor; start immediately regardless of CD4; check HLA-B*5701 before abacavir.
Significant needlestick from HIV+ source → start 3-drug PEP within 1 hour; continue for 28 days; test at baseline and 12 weeks.
Post-operative pain → multimodal analgesia: regular paracetamol + NSAID + PRN opioid; this is the ERAS standard.
Medicines optimisation = review each drug's benefit vs harm in context of the individual patient; consider deprescribing where risks outweigh benefits.
Severe hepatic impairment → reduce paracetamol to max 2g/day; avoid NSAIDs (hepatorenal syndrome) and codeine/morphine (encephalopathy).
UTI in breastfeeding → nitrofurantoin is safe; avoid fluoroquinolones and doxycycline; check for infant G6PD deficiency.
Childhood obesity first-line = family-based lifestyle intervention; medications only after lifestyle measures fail and only if age-appropriate.
Phenytoin has non-linear kinetics - small dose increases can cause toxicity, and nystagmus, ataxia, and dysarthria are cardinal signs requiring urgent level measurement.
Eczema treatment is stepwise - escalate from mild to moderate to potent topical steroids based on severity, always with emollients, and avoid potent steroids on the face in children per NICE CG57.
Moderate acne failing topical therapy requires oral antibiotics plus topical retinoid for 12 weeks - isotretinoin is reserved for severe or antibiotic-refractory acne per NICE guidelines.
Oestrogen-only HRT is appropriate after hysterectomy - progestogen is only needed with an intact uterus for endometrial protection per NICE NG23.
Labetalol is first-line for pre-eclampsia with a target BP of 135/85mmHg or lower - ACE inhibitors are contraindicated in pregnancy, and magnesium sulphate prevents eclamptic seizures per NICE NG133.
Combine an alpha-blocker with a 5ARI for BPH with prostate >30mL - 5ARIs take months for full effect and halve PSA levels per NICE CG97 and CombAT trial.
High-dose PERT with dietitian support is essential for EPI in pancreatic cancer - this improves nutrition, quality of life, and tolerance of chemotherapy.
Short bowel syndrome requires antisecretory and antimotility agents alongside optimised oral nutrition - sodium-rich ORS, loperamide, and PPI are key, and PN is weaned gradually.
Maintenance fluids are 25-30mL/kg/day with sodium, potassium, and glucose - distinguish from resuscitation and replacement fluids, and avoid excessive 0.9% saline per NICE CG174.
Correct magnesium alongside potassium for refractory hypokalaemia - oral replacement is first-line for mild-moderate cases, and IV potassium maximum rate is 10mmol/hr peripherally.
When oral iron is not tolerated or fails, give IV iron (ferric carboxymaltose or ferric derisomaltose) - a single infusion corrects deficiency rapidly, with anaphylaxis risk requiring trained staff and 30-minute observation per BSH guidance.
De-escalate antibiotics based on culture results - switch from broad IV to narrow oral when the patient improves, and this is fundamental to antimicrobial stewardship per NICE NG15.
Switch antibiotics based on culture sensitivities when empirical therapy fails - parenteral therapy is needed for sepsis, and gentamicin requires level monitoring in renal impairment per NICE NG109.
Voriconazole is first-line for invasive aspergillosis - fluconazole has no Aspergillus activity, and treatment should not be delayed for biopsy in high-risk patients per NICE guidelines.
Start ART immediately regardless of CD4 count - in HIV/HBV co-infection, the backbone must include tenofovir and emtricitabine, and never stop these without HBV cover per BHIVA guidelines.
Surgical antibiotic prophylaxis is a single IV dose at induction - for colorectal surgery, cover Gram-negatives and anaerobes, and avoid prolonged postoperative courses per NICE NG125.
Halve premixed insulin on the morning of short procedures - VRII is for longer fasting or poor control, and monitor glucose hourly per JBDS perioperative guidelines.
Medicines optimisation reviews each drug for indication, dose, safety, and adherence - check inhaler technique, uptitrate proven therapies, remove duplications, and involve the patient per NICE NG5.
In severe frailty, deprescribe preventive medications and focus on comfort - use STOPPFrail criteria, and every medication should justify its continuation against the patient's goals of care.
Oral-to-SC morphine conversion divides by 2 - combine morphine, midazolam, and an antiemetic in the syringe driver, and always prescribe breakthrough doses per palliative care guidelines.
If peaks are toxic and troughs are subtherapeutic, reduce the individual dose but give it more frequently - or switch to a modified-release formulation.
COPD exacerbation with pH 7.25-7.35 and PaCO2 >6 kPa = NIV/BiPAP - it reduces mortality and intubation rates (BTS/ICS 2016, NICE NG115); avoid uncontrolled high-flow oxygen.
DKA = NaCl first (1 L/1 h), FRII 0.1 units/kg/h, continue long-acting insulin, add KCl when K⁺ <5.5, add 10% dextrose when glucose <14, and stop only when ketones <0.6 - JBDS protocol.
Paediatric obesity management is primarily lifestyle-based - orlistat is the only pharmacological option for ≥12 years with severe comorbidities after failed lifestyle intervention.
Fasting glucose reflects basal insulin adequacy - increase basal insulin by 2-4 units every 3 days until at target.
In AKI, stop the 'triple whammy' (ACEi/ARB + NSAID + diuretic) plus metformin - use sick day rules to prevent drug-induced AKI.
PPV increases with prevalence; NPV decreases with prevalence - always consider the clinical setting when interpreting predictive values.
Type 2 = PaCO2 >6 kPa - control oxygen to 88-92% SpO2 and initiate NIV if pH drops below 7.35.
For severe hypoglycaemia with IV access: give IV 20% dextrose - if no IV access, give IM glucagon 1 mg. Always investigate and address the cause.
Ferritin is falsely elevated in inflammation - use transferrin saturation (<20%) and sTfR to diagnose iron deficiency in patients with concurrent inflammatory conditions.
Folic acid 5 mg (not 400 mcg) for high-risk pregnancies - this includes women on anti-epileptic drugs, diabetes, or previous NTD.
Lithium monitoring = level every 3 months, U&E every 6 months, TFTs every 6 months - therapeutic range is 0.4-1.0 mmol/L (12-hour trough).
Vancomycin trough monitoring: 10-15 for simple infections, 15-20 for serious infections - adjust dose and recheck until target achieved.
Always correct phenytoin for albumin - a 'sub-therapeutic' measured level may actually be therapeutic when protein binding is accounted for.
Ciclosporin has a narrow therapeutic index and numerous CYP3A4 interactions - always check for drug interactions before prescribing concurrent medications.
Tacrolimus causes NODAT (diabetes) and nephrotoxicity - monitor trough levels, glucose, and renal function closely post-transplant.
Uncomplicated lower UTI in a non-pregnant woman with a positive dipstick - nitrofurantoin 100 mg MR BD for 3 days first-line (NICE NG109); MSU only for treatment failure, recurrence, pregnancy or complicated UTI.
AF management = rate control (beta-blocker first-line) + anticoagulation (DOAC if CHA₂DS₂-VASc ≥2 male, ≥3 female).
Symptomatic complete heart block = IV atropine → temporary pacing - always review and stop AV-nodal blocking drugs.
AUDIT-C identifies risky drinking - brief intervention is the most cost-effective treatment for non-dependent harmful alcohol use.
In severe cancer pain, skip Step 2 and start oral morphine per NICE NG140 - always co-prescribe laxatives and antiemetics with opioid initiation.
Paracetamol overdose above the treatment nomogram = IV NAC immediately - most effective within 8 hours but beneficial even if delayed.
In a forest plot, if the overall diamond does NOT cross the line of no effect (OR/RR = 1), the pooled result is statistically significant.
NNH = 1/ARI - a lower NNH means more frequent harm. Always weigh NNT against NNH when making prescribing decisions.
The Hartford nomogram guides dosing INTERVAL, not dose - if the level is in the q36h zone, extend the interval but give the same dose.
Warfarin for mechanical valves (target 2.5-3.5) - DOACs are contraindicated. Make small dose adjustments (10-20%) and recheck INR in 1 week.
Levothyroxine = take on an empty stomach, 30 min before food, with water only - separate from calcium, iron, antacids, and PPIs by ≥4 hours.
A safe prescription requires drug, dose with units, route, frequency, duration, patient ID, and legible prescriber details - all must be present.
SIADH = euvolaemic hyponatraemia - fluid restrict and treat the cause (often SSRIs or carbamazepine); 0.9% saline can worsen it, and correct slowly to avoid osmotic demyelination (European hyponatraemia guideline).
All suspected TIAs need aspirin 300 mg and specialist review within 24 hours - NICE no longer uses ABCD2 to determine urgency.
When the time of paracetamol overdose is uncertain, START NAC - do not wait for a 'perfect' level, as the risks of under-treating far outweigh the risks of NAC.
Vitamin D deficiency (<25 nmol/L) requires a loading regimen - 50,000 IU weekly × 6 weeks followed by lifelong maintenance.
Valproate in women of childbearing age = MHRA Pregnancy Prevention Programme mandatory - it carries the highest teratogenic risk of all anti-epileptics.
Sympathomimetic toxicity = IV benzodiazepines plus active cooling; avoid haloperidol; and always check sodium for MDMA-related hyponatraemia (TOXBASE).
BTS/SIGN acute asthma severity: moderate 50-75%, severe 33-50%, life-threatening <33% - treat severe with nebulisers + steroids + oxygen.
QRISK3 ≥10% = offer atorvastatin 20 mg after shared decision-making - lifestyle advice is equally important and should always accompany pharmacological treatment.
Large symptomatic pleural effusion = therapeutic aspiration for relief + send fluid for analysis - always determine if transudative (treat cause) or exudative (investigate cause).
GCS ≤8 = intubate and protect airway - urgent CT and neurosurgical referral are mandatory for traumatic brain injury with lateralising signs.
Potency = position on x-axis (EC50, left = more potent); efficacy = maximum effect on y-axis (Emax) - these are distinct pharmacological properties.
High sensitivity = good at ruling OUT (SnNOut), high specificity = good at ruling IN (SpPIn) - PPV depends heavily on prevalence.
Always check weight before prescribing paracetamol - patients <50 kg require 15 mg/kg per dose (max 60 mg/kg/day), NOT the standard 1 g dose.
ACEi + spironolactone in CKD = high hyperkalaemia risk - always monitor K+ within 1 week of starting or dose-changing these drugs.
Theophylline has a narrow therapeutic index - always check for CYP1A2 interactions before prescribing concurrent antibiotics, especially macrolides and fluoroquinolones.
Raised ALP with normal GGT = bone origin - in a cancer patient with bone pain, always consider metastatic disease.
In high-probability PE (Wells >6), start treatment-dose anticoagulation immediately - do not wait for imaging confirmation.
If CO2 is high but HCO3 is low (or normal), suspect a mixed respiratory + metabolic acidosis - use the expected compensation formulas to confirm.
CRP >100 with systemic features suggests significant infection requiring IV antibiotics - always assess for sepsis using NEWS score and Sepsis Six bundle.
High-risk peptic ulcer bleeding (Forrest Ia/Ib/IIa) = endoscopic therapy + IV PPI infusion for 72 hours - always test for H. pylori.
Pernicious anaemia = lifelong IM hydroxocobalamin - oral B12 is NOT effective when intrinsic factor is absent.
Review antibiotics at 48-72h - if improving, switch IV to oral to reduce risks and promote antimicrobial stewardship.
Procalcitonin >0.5 strongly supports bacterial infection - use it to guide antibiotic initiation, escalation, and duration.
Neutropenic sepsis = antibiotics within 1 HOUR - this is a time-critical emergency with significant mortality if treatment is delayed.
HIT = stop ALL heparin + start argatroban/fondaparinux - NEVER give LMWH (cross-reacts), warfarin (causes necrosis), or platelets (worsens thrombosis).
AIT type 2 = destructive thyroiditis with low vascularity = treat with steroids; AIT type 1 = excess synthesis with high vascularity = treat with carbimazole.
Hyperkalaemia with ECG changes = calcium gluconate FIRST for cardioprotection, THEN insulin-dextrose to lower K+ - always arrange definitive treatment (dialysis or K+ removal).
Lactate >2 = sepsis concern; >4 = septic shock - the Sepsis Six must be completed within 1 hour; delays increase mortality by 7.6% per hour.
Digoxin therapeutic range is 1.0-2.0 ng/mL but optimal is 0.5-1.0 for heart failure - always check potassium and renal function alongside levels.
STEMI = aspirin + prasugrel/ticagrelor loading for primary PCI - time is myocardium, so activate the PCI pathway immediately.
Rinse mouth and spit after using ICS - use a spacer with MDI to reduce oral thrush risk; treat with nystatin or miconazole; use the lowest effective ICS dose.
Tramadol lowers seizure threshold - avoid in epilepsy and with serotonergic drugs; the combination with SSRIs also risks serotonin syndrome.
Always check U&Es within 2 weeks of starting an ACEi - hyperkalaemia risk is amplified in CKD and with concurrent potassium-sparing agents.
Aromatase inhibitor arthralgia affects up to 50% of patients - exercise helps; consider switching AI or to tamoxifen; always assess bone density and provide bone protection.
Tramadol + venlafaxine/SSRIs = serotonin syndrome risk - avoid this combination; use non-serotonergic analgesics with antidepressants.
ACE inhibitors cause dry cough via bradykinin accumulation - switch to an ARB, do not try another ACE inhibitor.
Metformin must be stopped in AKI and during acute illness - teach patients sick day rules to prevent lactic acidosis.
Sulfonylureas cause insulin-independent hypoglycaemia - reduce dose in elderly, renal impairment, and poor oral intake.
SGLT2 inhibitor DKA has near-normal glucose - always check ketones if acidotic, even when glucose is not markedly elevated.
SGLT2 inhibitors + perineal pain/swelling = consider Fournier's gangrene - this is a surgical emergency requiring immediate debridement.
GLP-1 agonists can cause pancreatitis - stop immediately if suspected and never rechallenge; contraindicated in previous pancreatitis.
Always examine insulin injection sites - lipohypertrophy from repeated same-site injection causes erratic absorption and poor control; rotate sites systematically.
Pioglitazone is contraindicated in any degree of heart failure - stop immediately if oedema, weight gain, or breathlessness develop.
Pioglitazone increases bladder cancer risk with prolonged use - contraindicated in active/previous bladder cancer and uninvestigated haematuria.
Amiodarone corneal microdeposits occur in nearly all patients - they are usually benign, but optic neuropathy is a rare serious complication requiring urgent action.
IV furosemide + aminoglycosides = synergistic ototoxicity risk - infuse furosemide slowly (max 4mg/min) and avoid this combination when possible.
Spironolactone causes gynaecomastia via anti-androgen effects - switch to eplerenone if symptomatic, as it has minimal anti-androgen activity.
FINISH mnemonic for SSRI discontinuation - paroxetine and venlafaxine have the highest risk; always taper gradually, never stop abruptly.
Mirtazapine causes significant weight gain via H1 and 5-HT2C blockade - sedation is paradoxically greater at lower doses; discuss weight monitoring with patients.
NSAIDs reduce renal lithium clearance and cause toxicity - always check lithium interactions before prescribing new medications to patients on lithium.
Lithium NDI = failure to respond to desmopressin (distinguishes from cranial DI) - amiloride is the treatment of choice if lithium must continue.
Test HLA-B*1502 before starting carbamazepine in South-East Asian patients - SJS/TEN is life-threatening and requires immediate drug cessation and specialist care.
Phenytoin causes gingival hypertrophy in up to 50% of patients - maintain strict oral hygiene and consider switching to a newer antiepileptic if problematic.
Start bone protection when prednisolone ≥7.5mg daily is planned for ≥3 months - alendronate + calcium/vitamin D is first-line; DEXA scan for baseline.
Always co-prescribe a laxative when starting regular opioids - constipation does not develop tolerance; consider naloxegol if standard laxatives fail.
Pregabalin causes dose-dependent weight gain and peripheral oedema - consider duloxetine as an alternative for diabetic neuropathy if metabolic effects are problematic.
Start allopurinol low (100mg) and go slow - DRESS risk is increased in renal impairment and HLA-B*5801 carriers; test in Han Chinese/Korean/Thai populations.
Fluoroquinolones + corticosteroids = high risk of Achilles tendon rupture - MHRA restricts use; avoid in patients >60, on steroids, or with renal impairment.
Trimethoprim blocks ENaC like amiloride - avoid in patients on ACEi + spironolactone + amiloride; check potassium if unavoidable.
Amphotericin B deoxycholate causes nephrotoxicity in up to 80% - use liposomal formulation when possible; pre-hydrate with IV saline and monitor K+/Mg2+ daily.
Tamoxifen is an oestrogen agonist in the endometrium - counsel patients to report vaginal bleeding immediately; investigate post-menopausal bleeding urgently via 2-week wait.
Always co-prescribe mesna with cyclophosphamide - acrolein causes haemorrhagic cystitis and long-term bladder cancer risk; ensure adequate hydration and frequent voiding.
Checkpoint inhibitor thyroiditis follows a biphasic pattern (thyrotoxicosis → hypothyroidism) - manage symptomatically; levothyroxine for permanent hypothyroidism; immunotherapy can usually continue.
Screen all patients for latent TB before anti-TNF (NICE NG129; BNF; BSR/BSG/BAD). Treat latent TB first - typically isoniazid + rifampicin for 3 months. Also screen for hepatitis B and C.
High-dose salbutamol causes tremor, tachycardia, and hypokalaemia - monitor K+ after repeated nebulised doses; correct hypokalaemia to prevent arrhythmias.
Treat metoclopramide-induced dystonia with IV procyclidine 5mg - MHRA restricts use to max 5 days; avoid in under-20s; young women are at highest risk.
ACE inhibitor angioedema has no urticaria, is more common in Afro-Caribbean patients, and requires permanent drug discontinuation.
Statin myopathy is dose-dependent - check CK, and if >5x ULN with symptoms, stop the statin immediately.
Monitor LFTs every 6 months on amiodarone - stop if transaminases exceed 3x ULN or clinical hepatitis develops.
Verapamil causes constipation in up to 40% of patients - warn patients, start laxatives proactively, and consider alternatives if problematic.
In DAPT bleeding, stop clopidogrel but continue aspirin to balance stent thrombosis risk - treat the bleeding source and plan early clopidogrel restart.
TCAs have potent anticholinergic effects - avoid in elderly patients with BPH, glaucoma, or constipation; use duloxetine or gabapentin for neuropathic pain instead.
Methotrexate pneumonitis is a hypersensitivity reaction (not dose-dependent) - stop methotrexate, give steroids, and exclude Pneumocystis infection.
Tacrolimus tremor affects up to half of patients and is dose-dependent - reduce dose if levels permit, or consider propranolol for symptomatic relief.
Co-amoxiclav is one of the 4Cs (co-amoxiclav, cephalosporins, ciprofloxacin, clindamycin) - treat C. difficile with oral vancomycin; never give loperamide.
Hydroxychloroquine retinopathy is irreversible - screen annually from year 5; keep dose ≤5mg/kg actual body weight; stop immediately if OCT shows maculopathy.
Imatinib periorbital oedema affects up to 70% of patients - it is due to PDGFR inhibition, not heart failure; usually manageable with conservative measures.
The ACEi + NSAID + dehydration combination is a classic cause of AKI - teach patients sick day rules.
Asthma + nasal polyps + NSAID sensitivity = Samter's triad - avoid all COX-1 inhibitors, paracetamol is safe.
Beta-blocker + digoxin together increase bradycardia risk - monitor HR carefully and titrate doses; IV atropine is first-line for symptomatic bradycardia.
Venlafaxine causes dose-dependent hypertension - monitor BP before starting and at each dose increase; risk increases significantly above 150mg daily.
Stop colchicine at the first sign of diarrhoea - GI symptoms signal toxicity; avoid CYP3A4 inhibitors (macrolides, azoles) which can cause fatal colchicine accumulation.
Never stop prednisolone abruptly after >3 weeks of supraphysiological doses - taper gradually; treat adrenal crisis with IV hydrocortisone 100mg stat.
Rituximab infusion reactions are cytokine-mediated, not truly allergic - stop infusion, treat symptoms, then restart at slower rate; pre-medicate all patients.
Long-term PPIs cause hypomagnesaemia - check Mg2+ periodically, especially with concurrent diuretics; review PPI need regularly using the lowest dose for the shortest duration.
QRS >100ms in TCA overdose = give IV sodium bicarbonate 8.4% - this is the key intervention that saves lives; never use phenytoin for TCA seizures.
Warn about orange secretions before starting rifampicin - contact lenses will stain permanently; rifampicin is a potent enzyme inducer that reduces OCP efficacy.
Montelukast causes neuropsychiatric ADRs, especially in children - warn parents about nightmares, behavioural changes, and mood disturbance; stop if symptoms develop.
Screen for hydroxychloroquine retinopathy annually after 5 years - stop immediately if OCT shows early retinal changes; toxicity is irreversible; risk increases with dose >5 mg/kg/day and duration >5 years.
Check sodium 2-4 weeks after starting thiazides in elderly patients - hyponatraemia risk is highest in older women with low body weight.
NSAIDs are nephrotoxic in CKD patients - avoid or use with extreme caution, and never combine with ACEi and diuretic without careful monitoring.
IM adrenaline 1:1000 (500mcg) into the thigh is first-line for anaphylaxis - never give IV adrenaline at cardiac arrest concentration outside of cardiac arrest.
Amoxicillin + EBV = predictable non-allergic rash - this is NOT true penicillin allergy; do not mislabel the patient as allergic.
Flucloxacillin causes delayed-onset cholestatic jaundice (1-6 weeks post-treatment) - risk increases with age >55, female sex, and courses >14 days; associated with HLA-B*5701.
Pyrazinamide is the most hepatotoxic first-line TB drug - identify it by sequential re-introduction; if it cannot be tolerated, use a 9-month isoniazid and rifampicin based regimen with ethambutol in the intensive phase.
Valproate hepatotoxicity is most dangerous in children under 3 on polytherapy - monitor LFTs in the first 6 months and stop immediately if liver dysfunction develops.
Always co-prescribe a PPI with NSAIDs in patients aged >65 or with other GI risk factors - never prescribe NSAIDs without assessing GI risk.
Amiodarone is 37% iodine - causes both hypo- and hyperthyroidism; monitor TFTs every 6 months during and after treatment.
INR 5-8 without bleeding = withhold 1-2 doses, investigate cause, recheck INR; oral vitamin K only if approaching 8 or high bleeding risk; IV vitamin K for major bleeding.
The Hartford nomogram uses a single 6-14h post-dose level to guide dosing interval - q24h zone means continue current dosing; not valid for endocarditis, burns, or dialysis.
Vancomycin trough 15-20 mg/L for deep infections, 10-15 mg/L for uncomplicated; increase dose if subtherapeutic; AUC/MIC dosing is increasingly preferred.
In hypoalbuminaemia, correct the total phenytoin level (Sheiner-Tozer) or measure the free level - a low total level can be therapeutic, so do not blindly increase the dose (BNF).
Carbamazepine autoinduces its own metabolism via CYP3A4 - levels fall after 2-4 weeks requiring dose increase; recheck levels 3-4 weeks after starting.
Azathioprine requires lifelong FBC monitoring - weekly initially, then extending to 3-monthly; never stop monitoring regardless of TPMT status or treatment duration.
Early post-transplant tacrolimus targets are higher (10-15 ng/mL) - subtherapeutic levels risk rejection; monitor at least twice weekly initially; CYP3A4 interactions significantly alter levels.
Clozapine requires mandatory blood monitoring - weekly for 18 weeks, fortnightly to 1 year, monthly thereafter; patients must be registered; no blood result = no clozapine supply.
Amiodarone requires baseline TFTs, LFTs, CXR, TLCO, and eye exam - monitor TFTs and LFTs every 6 months during and for 12 months after stopping treatment.
TLCO is the most sensitive baseline marker for amiodarone pulmonary toxicity - measure before starting and repeat if respiratory symptoms develop; a >15-20% decline suggests toxicity.
Check U&Es within 1-2 weeks of starting ACEi - creatinine rise up to 30% is acceptable; stop if rise >30% or K+ >5.5; recheck after each dose increase.
Check CK only on symptoms - not routinely; CK >10× ULN = possible rhabdomyolysis (stop statin, hydrate); always check TSH (treat hypothyroidism before restarting); review CYP3A4 interactions (BNF / NICE NG238).
Antipsychotics require comprehensive metabolic monitoring - weight, glucose, lipids, BP; olanzapine and clozapine have the highest metabolic risk; patients with SMI have 15-20 year reduced life expectancy.
SSRIs in under-25s require weekly monitoring for the first 4 weeks - assess for suicidality at each visit; fluoxetine is the only SSRI licensed for depression in under-18s.
Check U&Es within 1 week of starting spironolactone with ACEi - hyperkalaemia risk is additive; stop if K+ >6.0; monitor more frequently in CKD.
Monitor calcium, phosphate, and PTH regularly in CKD - alfacalcidol causes hypercalcaemia; reduce dose if calcium is elevated; manage phosphate with binders and dietary restriction.
Check TFTs every 6 months on amiodarone - continue monitoring for 12 months after stopping; amiodarone causes both hypo- and hyperthyroidism due to iodine excess.
Start low, go slow in elderly - renal function is overestimated by creatinine; review polypharmacy using STOPP/START; calculate anticholinergic burden; monitor for drug interactions.
Metformin - reduce at eGFR 30-45 (max 1g/day), stop at eGFR <30; teach patients sick day rules; monitor renal function every 3-6 months.
Each DOAC has specific renal thresholds - rivaroxaban reduces to 15mg at eGFR 15-49; apixaban is the least renally dependent (to eGFR 15); check eGFR at least annually.
Daily weight monitoring in heart failure - weight gain >2kg in 2-3 days indicates fluid retention; increase diuretic dose and check U&Es; contact heart failure team if no response within 48 hours.
Steroid hyperglycaemia peaks in the afternoon/evening - morning fasting glucose underestimates the problem; monitor CBG at lunch, dinner, and bedtime; morning NPH insulin matches the prednisolone glycaemic profile.
Apply STOPP/START systematically - stop Z-drugs and anticholinergics in fallers; start bone protection in osteoporosis; reducing anticholinergic burden is a key falls prevention strategy.
Calculate anticholinergic burden in elderly patients with cognitive decline - stop anticholinergic drugs in dementia patients as they antagonise cholinesterase inhibitors; use ACB scale to guide deprescribing.
MHRA Drug Safety Updates represent current standard of care - professional duty to be aware and respond; failure to act may constitute negligence if harm results; sign up for MHRA alerts.
Morning hyperglycaemia + nocturnal hypos = Somogyi phenomenon - reduce basal insulin, don't increase it; 3am glucose check distinguishes from Dawn phenomenon; CGM provides superior overnight data.
CGM provides real-time glucose data with hypo/hyper alerts - NICE recommends for impaired awareness of hypoglycaemia; it measures interstitial (not blood) glucose with a 5-15 minute lag; time-in-range is the key outcome metric.
Flash monitoring requires scanning (original version has no automatic alarms) - provides painless, frequent glucose data; factory-calibrated, no finger-prick calibration needed; newer versions include alarms.
Monitor growth annually in children on ICS - high-dose ICS can reduce growth velocity by 0.5-1cm/year; use the lowest effective dose; step down when control is achieved; fluticasone is more potent than beclometasone.
Non-adherence affects ~50% of patients - assess non-judgmentally; simplify regimens (once-daily, combination tablets); address beliefs and barriers; use the Necessity-Concerns Framework; NICE CG76 provides comprehensive guidance.
DOACs lack evidence in Child-Pugh B/C liver disease - warfarin with specialist monitoring may be used; bleeding and thrombosis risks coexist; MDT discussion is essential.
Basiliximab is an IL-2R antagonist given as 2 doses at transplant - monitor for infusion reactions; minimal specific monitoring needed; safer profile than depleting induction agents; does not require drug level monitoring.
Post-thrombolysis - continuous cardiac monitoring for arrhythmias, serial ECGs for ST resolution at 60-90 minutes, frequent BP checks, and active bleeding surveillance; rescue PCI if ST fails to resolve.
Monitor for anaphylaxis during IV iron infusion - check Hb/ferritin at 4-8 weeks; watch for hypophosphataemia (especially ferric carboxymaltose); MHRA warning about phosphate effects; observe for 30 minutes post-infusion.
Compassionate use requires enhanced monitoring and ADR reporting - safety data is incomplete; report ALL suspected ADRs; obtain informed consent; comprehensive clinical and laboratory monitoring is essential.
Thiazides increase lithium levels - reduce lithium dose by ~50% if co-prescribing; always recheck levels when interacting drugs are started.
Severe lithium toxicity with level >2.5 mmol/L and neurological features = haemodialysis; charcoal does not bind lithium; IV saline enhances renal excretion.
INR >8 without bleeding = stop warfarin + oral vitamin K 1-5mg + recheck INR next day; investigate and address the cause (drug interaction, diet, illness).
Always take digoxin levels at least 6 hours post-dose - samples taken earlier are falsely elevated due to the distribution phase; never adjust doses based on early samples.
Digoxin toxicity can occur at 'therapeutic' levels when potassium is low - always maintain K⁺ >3.5 mmol/L; monitor U&Es regularly with concurrent diuretics.
Monitor ciclosporin troughs at 12 hours post-dose - target ranges decrease over time post-transplant; supratherapeutic levels cause nephrotoxicity, hypertension, and hyperkalaemia.
Monitor FBC regularly on mycophenolate - leucopenia and diarrhoea are dose-dependent; reduce dose if WCC falls; exclude CMV infection as a differential cause.
All conventional DMARDs require regular blood monitoring - each drug has specific requirements; shared care agreements define GP responsibilities; never prescribe without current results.
Stop ACEi if creatinine rises >30% from baseline - investigate for renal artery stenosis; a rise ≤30% is acceptable and expected; concurrent spironolactone increases risk.
Continue iron for 3 months after Hb normalises to replete stores - monitor FBC and ferritin; target ferritin >50-100 μg/L for adequate stores; investigate if Hb doesn't rise ≥20 g/L per month.
Check LFTs before starting systemic antifungals and during treatment if prolonged - terbinafine after 4 weeks; azoles more frequently; stop if significant LFT abnormality or symptoms develop.
Anti-HBc positive patients on rituximab need HBV DNA monitoring every 1-3 months - reactivation risk is high; consider prophylactic antivirals; monitor for 12 months after stopping.
TDM is indicated for drugs with a narrow therapeutic index - lithium, phenytoin, digoxin, theophylline, aminoglycosides, vancomycin, and calcineurin inhibitors are the key examples.
Burns patients need higher aminoglycoside doses due to increased Vd and augmented renal clearance - monitor levels frequently (often daily); standard dosing protocols are inadequate.
Loading doses rapidly achieve therapeutic levels for drugs with long half-lives - the loading dose depends on volume of distribution; the maintenance dose depends on clearance (renal/hepatic function).
Hepatic dose adjustment has no simple formula - avoid hepatotoxins, reduce hepatically metabolised drug doses, use Child-Pugh score to guide, and monitor closely.
Avoid NSAIDs in CKD, especially with ACEi + diuretic (triple whammy) - use topical NSAIDs, physiotherapy, or non-NSAID alternatives; COX-2 inhibitors have equal renal risk.
Carbimazole + sore throat + fever = urgent FBC; neutrophils <1.0 = stop permanently, never rechallenge; PTU has cross-reactivity; counsel all patients before starting.
Review PPI prescriptions annually - monitor Mg, Ca, B12, and iron during long-term use; MHRA warns about hypomagnesaemia; use lowest dose for shortest duration.
Individualise HbA1c targets in elderly patients - relax to 58-64 mmol/mol in frail patients with comorbidities and hypoglycaemia risk; tight control does more harm than good in this population.
Switch from mixed to basal-bolus insulin in hospital - allows flexible dosing with erratic eating; monitor CBG at least QDS; VRIII only for NBM, DKA/HHS, or perioperative settings.
Review bisphosphonate treatment at 3-5 years with DEXA - consider drug holiday after 5 years in low-risk patients; continue in high-risk; monitor for atypical fractures and osteonecrosis of jaw.
After radioactive iodine - check TFTs every 4-6 weeks for 6 months, then annually for life; hypothyroidism develops in >80% and is the intended outcome; start levothyroxine when hypothyroid.
Total phenytoin in hypoalbuminaemia is misleadingly low - calculate albumin-adjusted level or request free level; never increase dose based on low total level alone in liver disease.
Monitor tacrolimus trough levels regularly - avoid grapefruit and CYP3A4 inhibitors; prescribe by brand name; supratherapeutic levels cause nephrotoxicity and tremor; adjust dose and recheck within 3-5 days.
Sirolimus is not nephrotoxic but requires monitoring of lipids, FBC, mouth ulcers, wound healing, and proteinuria - multiple ADRs differ from calcineurin inhibitors; monitor trough levels and adjust for CYP3A4 interactions.
Check FBC at least 6h post-transfusion - monitor fluid balance especially in heart failure; each unit raises Hb ~10 g/L; watch for delayed reactions (2-14 days); TACO is the commonest transfusion hazard.
ESA target Hb is 100-120 g/L - do NOT target higher (increased cardiovascular risk); monitor Hb monthly, iron studies 1-3 monthly, and blood pressure; reduce ESA dose if Hb approaches 120.
Check calcium within 1 week of starting cinacalcet and after each dose change - do not start if calcium is low; can cause symptomatic hypocalcaemia; titrate dose to PTH target every 2-4 weeks.
Codeine is contraindicated in breastfeeding (MHRA warning) - CYP2D6 ultra-rapid metabolisers produce excessive morphine in breast milk; sertraline and ibuprofen are safe; always check the BNF and specialist lactation resources.
Avoid morphine and codeine in severe CKD - M6G accumulates causing prolonged toxicity; use fentanyl or buprenorphine instead; convert doses carefully.
New warfarin requires frequent INR checks - weekly until stable, then gradually extend to 4-12 weekly; any change in medication, diet, or health status requires retesting.
Methotrexate requires at least monthly FBC, U&Es, and LFTs - blood results must be available before each prescription; red flags trigger immediate review.
Nitrate headaches improve over 1-2 weeks - monitor BP lying and standing; ensure nitrate-free interval to prevent tolerance; paracetamol helps initial headaches.
Always take lithium levels at 12 hours post-dose - earlier samples overestimate the level; for evening dosing, a morning blood test provides the correct timing.
Always transcribe insulin exactly as the patient takes it at home - dose, type, timing, and device. Errors cause hypo/hyperglycaemia.
EVERY medical admission needs VTE risk assessment - enoxaparin 40mg SC OD if risk factors present and no contraindications.
ACEi + spironolactone = check K+ and renal function within 1 week of starting, then regularly. High risk of hyperkalaemia, especially in CKD.
Methotrexate = ALWAYS co-prescribe folic acid 5mg weekly (different day) - reduces side effects without reducing efficacy.
Alcohol withdrawal + poor nutrition = IV Pabrinex (thiamine) BEFORE glucose/food - prevents irreversible Wernicke-Korsakoff syndrome.
Diltiazem/verapamil = CONTRAINDICATED in HF with reduced EF (negative inotrope). Use amlodipine if a CCB is needed.
SSRI + tramadol = serotonin syndrome risk. Tramadol is unique among opioids in having serotonergic activity. Use codeine or morphine instead.
ACEi/ARBs = STOP immediately if pregnant - switch to labetalol. They are teratogenic throughout pregnancy (renal agenesis, oligohydramnios).
Aspirin IS an NSAID - aspirin-exacerbated respiratory disease = severe bronchospasm risk. Needs specialist input, not routine administration.
Oral to IV/SC morphine = divide by 2-3. NEVER transcribe oral doses as IV without conversion - potentially fatal overdose.
Simvastatin + CYP3A4 inhibitor (clarithromycin) = rhabdomyolysis risk. Withhold statin or use azithromycin instead.
Codeine is CONTRAINDICATED in breastfeeding (MHRA) - ultra-rapid CYP2D6 metabolisers produce toxic morphine levels in breast milk.
Fluoroquinolones (ciprofloxacin, levofloxacin) = avoid in children and growing adolescents - tendon/cartilage damage risk.
Non-selective beta-blocker (propranolol) + asthma = ABSOLUTE contraindication - severe bronchospasm. Beta-2 blockade causes wheeze and blocks salbutamol rescue.
Gentamicin in obesity = dose on adjusted/ideal body weight, NOT actual weight - adipose tissue does not distribute aminoglycosides.
Current BNF - oral morphine 60 mg/day = fentanyl 25 micrograms/hour; 120 mg/day = 50 micrograms/hour. Use a single named conversion chart; opioid conversion errors can be fatal.
INR 5-8 with no bleeding = withhold 1-2 doses, reduce dose, recheck in 2-5 days. IV vitamin K is for major bleeding only.
Co-trimoxazole = trimethoprim + SULFAMETHOXAZOLE - check sulfonamide allergy status. Use dapsone or atovaquone for PCP prophylaxis if allergic.
Drug allergy = document on drug chart + EPR + wristband + notes - all locations. Failure to document risks re-exposure and harm.
Mild egg allergy = flu vaccine is safe in primary care. Egg anaphylaxis = vaccinate with caution in a setting with resuscitation facilities.
IV potassium = max 10mmol/hour peripherally. NEVER give as a bolus - fatal cardiac arrest. Concentrated KCl is a high-risk medication.
A complete prescription needs: drug, dose, route, frequency, start date, signature - omitting any element is a prescribing error.
Opioids in severe liver disease = avoid or use with extreme caution - precipitate hepatic encephalopathy. Use paracetamol (reduced dose) instead.
Methotrexate ONCE WEEKLY only - daily dosing is an NPSA 'never event' causing fatal pancytopaenia. Always write the specific day.
Enzyme-inducing AED (carbamazepine) + COC = contraceptive failure. Use copper IUD or Depo-Provera instead.
Trimethoprim in first trimester = avoid (folate antagonist, neural tube defect risk). Use nitrofurantoin or cefalexin instead.
IV insulin bolus = immediate severe hypoglycaemia. SC insulin has gradual onset. Route errors with insulin are potentially fatal - always double-check.
Thiazide-induced severe hyponatraemia = NEVER restart - it WILL recur (idiosyncratic, not dose-dependent). Document and use alternative antihypertensive.
NSAID + severe CKD = contraindicated - use colchicine or prednisolone for acute gout when eGFR <30.
Amiodarone DOUBLES digoxin levels - halve the digoxin dose when starting amiodarone and monitor levels closely.
MAOI to SSRI = 2-week washout minimum. SSRI to MAOI = 1-week washout (5 weeks for fluoxetine). No overlap - fatal serotonin syndrome.
Metformin and eGFR - review dose at 45, reduce at 30-45, STOP below 30. Lactic acidosis is potentially fatal.
Valproate + women of childbearing potential = MHRA Pregnancy Prevention Programme mandatory. 10% malformation rate, 30-40% neurodevelopmental risk.
Nitrofurantoin is safe in early pregnancy BUT avoid at term (>36 weeks) - risk of neonatal haemolytic anaemia.
Digoxin dosing = adjust for renal function, weight, and age. Elderly + low weight + CKD = 62.5-125mcg, NOT the 'standard' 250mcg.
Decimal point errors cause 10-fold overdoses - ALWAYS double-check paediatric dose calculations. Write clearly and use independent verification.
LMWH in severe CKD (eGFR <30) = dose reduce or monitor anti-Xa, or use UFH instead - accumulation causes major bleeding.
Penicillin rash (not anaphylaxis) = cephalosporins can be used cautiously. Penicillin anaphylaxis = avoid cephalosporins without allergy testing.
Starting opioids = ALWAYS co-prescribe laxatives - tolerance does NOT develop to opioid constipation. Senna + Macrogol is standard.
Anaphylaxis = adrenaline 500mcg IM (1:1000). NEVER give 1:1000 IV - use 1:10,000 IV only in cardiac arrest or specialist settings.
Always reconcile medications accurately at admission - check drug name, dose, route, frequency, and timing against home records.
MR does not equal IR morphine - different pharmacokinetics, different dosing. Always specify formulation clearly to prevent dangerous errors.
NEVER prescribe two NSAIDs together - no additional benefit, doubled toxicity risk. Always check what the patient is already taking.
ALWAYS verify patient identity (name + DOB + hospital number + wristband) against drug chart before EVERY drug administration. Wrong-patient errors are preventable.
NSAID + risk factors (age >65, previous ulcer, antiplatelet) = MUST co-prescribe PPI per NICE CG184 and STOPP criteria; use lansoprazole with clopidogrel, not omeprazole (MHRA 2010).
Warfarin + macrolide (especially clarithromycin) = dangerously raised INR. Always check interactions before prescribing antibiotics to warfarin patients.
Clopidogrel + omeprazole/esomeprazole = reduced antiplatelet effect via CYP2C19 inhibition - switch to lansoprazole or pantoprazole if gastroprotection is needed.
Warfarin + cranberry juice = raised INR (CYP2C9 inhibition). MHRA has issued a safety warning - advise warfarin patients to avoid cranberry products.
Penicillin allergy (anaphylaxis) = avoid ALL penicillins (amoxicillin, flucloxacillin, co-amoxiclav, Tazocin). Co-amoxiclav IS a penicillin.
Long-term steroids (>=7.5mg pred for >=3 months) = calcium + vitamin D +/- bisphosphonate - glucocorticoid-induced osteoporosis is preventable.
Starting opioids = co-prescribe antiemetic PRN (cyclizine/haloperidol) AND laxative (always). Nausea settles in ~1 week; constipation does NOT.
LASA drug errors are a major safety concern. Common pairs: hydroxyzine/hydralazine, chlorpromazine/chlorpropamide, prednisolone/prednisone.
Schedule 2 CD prescription = total quantity in WORDS and FIGURES. Prescription valid for 28 days. Pharmacist must verify compliance.