Master Pharmacology
for PMDC NLE Step 1

What the PMDC NLE Step 1 Tests in Pharmacology

The PMDC NLE Step 1 Pharmacology section tests your ability to apply drug knowledge to clinical scenarios: selecting first-line therapy for common conditions (e.g., ACE inhibitors for diabetic nephropathy, metformin for type 2 diabetes), recognising adverse effects (e.g., statin-induced myopathy, NSAID-related GIT bleeding), and managing overdoses (e.g., N-acetylcysteine for paracetamol, naloxone for opioids). You must know mechanisms, contraindications (e.g., beta-blockers in asthma), and key prescribing guidelines (e.g., warfarin INR targets, antibiotic prophylaxis for rheumatic fever). Questions often present a patient with comorbidities and ask for the most appropriate drug or dose adjustment, requiring integration of pharmacology with physiology and pathology.

High-Yield Concepts

• Antihypertensives – First-Line Choices: First-line for uncomplicated hypertension: ACE inhibitors (e.g., ramipril) or ARBs (e.g., losartan) in patients <55 years; calcium channel blockers (e.g., amlodipine) or thiazide-like diuretics (e.g., indapamide) in patients ≥55 years or of Black African/Caribbean origin. Target BP <140/90 mmHg (clinic) or <135/85 mmHg (home). Avoid ACE inhibitors in pregnancy and bilateral renal artery stenosis.
• Antibiotics – Pneumonia Guidelines: For community-acquired pneumonia (CURB-65 score): low severity (0-1) – amoxicillin 500 mg TDS or doxycycline; moderate (2) – amoxicillin + clarithromycin; high (3-5) – IV co-amoxiclav + clarithromycin. For hospital-acquired pneumonia: piperacillin-tazobactam or a carbapenem (e.g., meropenem). Always consider local resistance patterns.
• Anticoagulants – Atrial Fibrillation: CHA₂DS₂-VASc score ≥2 in men or ≥3 in women: start DOAC (apixaban 5 mg BD, rivaroxaban 20 mg OD, edoxaban 60 mg OD, or dabigatran 150 mg BD) unless contraindicated (e.g., mechanical valve, severe renal impairment). Warfarin target INR 2.0-3.0. Use HAS-BLED score to assess bleeding risk but do not withhold anticoagulation solely for high score.
• Diabetes – Metformin and SGLT2 Inhibitors: First-line for type 2 diabetes: metformin, start 500 mg OD, increase to 2 g daily in divided doses. Contraindicated if eGFR <30 mL/min/1.73m² (stop if eGFR <45). Add SGLT2 inhibitor (e.g., dapagliflozin 10 mg OD) if established cardiovascular disease, heart failure, or CKD (eGFR ≥25). Monitor for euglycaemic DKA and genital infections.
• Opioid Analgesia – WHO Ladder: Step 1 (mild pain): paracetamol 1 g QDS ± NSAID (e.g., ibuprofen 400 mg TDS). Step 2 (moderate): weak opioid (e.g., codeine 30-60 mg QDS, tramadol 50-100 mg QDS). Step 3 (severe): strong opioid (e.g., morphine 5-10 mg oral solution 4-hourly, fentanyl patch). Always prescribe laxatives (e.g., senna) and antiemetics (e.g., metoclopramide) with opioids.
• Antidepressants – SSRIs First-Line: First-line for moderate-severe depression: sertraline 50 mg OD or citalopram 20 mg OD. Monitor for side effects (nausea, sexual dysfunction, hyponatraemia in elderly). Avoid MAOIs with SSRIs (serotonin syndrome risk). For anxiety disorders, start with low dose (e.g., escitalopram 5 mg). Consider mirtazapine if insomnia or weight loss.
• Bronchodilators – Asthma Stepwise: Step 1: inhaled short-acting beta-2 agonist (SABA, e.g., salbutamol 100-200 mcg PRN). Step 2: add low-dose inhaled corticosteroid (ICS, e.g., beclometasone 100-200 mcg BD). Step 3: add long-acting beta-2 agonist (LABA, e.g., formoterol). Step 4: increase ICS to high dose ± add tiotropium (LAMA). Step 5: consider oral prednisolone or biologic (e.g., omalizumab).
• Antiepileptics – Status Epilepticus: First-line: IV lorazepam 4 mg (or buccal midazolam 10 mg if no IV access). If persists after 10 minutes: second dose benzodiazepine. If still seizing: IV phenytoin 15-18 mg/kg (max 50 mg/min) or IV levetiracetam 60 mg/kg. Refractory: IV anaesthetic (e.g., propofol, thiopental) with ICU support. Check glucose and electrolytes urgently.

Common Traps in Pharmacology Questions

• Confusing first-line antihypertensives by age and ethnicity – the NICE guidelines differ for Black patients.
• Using amoxicillin alone for severe community-acquired pneumonia (CURB-65 ≥2) – you must add a macrolide.
• Prescribing warfarin instead of a DOAC for atrial fibrillation in a patient with a mechanical mitral valve – DOACs are contraindicated.
• Forgetting to adjust metformin dose or stop it when eGFR falls below 30 mL/min – risk of lactic acidosis.
• Selecting an NSAID for pain in a patient with CKD stage 4 (eGFR <30) – contraindicated due to nephrotoxicity.
• Administering naloxone for opioid overdose and forgetting the short half-life – patient may relapse into respiratory depression after 20-30 minutes.

How to Revise Pharmacology for the PMDC NLE Step 1

Focus on guideline-driven prescribing for common presentations: hypertension, diabetes, asthma, infections, and pain. Questions are often scenario-based, requiring you to choose the safest and most effective drug given age, comorbidities, and contraindications. Memorise key doses (e.g., amoxicillin 500 mg, metformin 500 mg) and monitoring parameters (e.g., INR for warfarin, renal function for metformin). Be ready to identify adverse effects from drug interactions (e.g., statin + clarithromycin increases myopathy risk). Practise interpreting clinical data (e.g., CURB-65, CHA₂DS₂-VASc) to guide therapy. Prioritise high-yield drug classes: ACEi/ARBs, statins, DOACs, SSRIs, beta-2 agonists, and antibiotics for respiratory and urinary infections. Avoid memorising rare drugs – the exam tests common, first-line choices and their pitfalls.

Practise it: MedLumen has 50 Pharmacology questions for the PMDC NLE Step 1, each with a full explanation and references.