I have all the content needed. Let me compile a comprehensive NEET PG-focused answer now.
Hypertension Pharmacology - NEET PG High-Yield Notes
BP Classification (ACC/AHA 2017)
| Category | Systolic | | Diastolic |
|---|
| Normal | <120 | and | <80 |
| Elevated | 120-129 | or | <80 |
| Stage 1 HTN | 130-139 | or | 80-89 |
| Stage 2 HTN | ≥140 | or | ≥90 |
Goal BP for most patients: <130/80 mmHg
Drug Classification - Antihypertensives
1. Diuretics
- Thiazides: Hydrochlorothiazide, Chlorthalidone, Indapamide
- Loop: Furosemide
- K+-sparing: Spironolactone, Eplerenone, Amiloride
2. RAAS Inhibitors
- ACE Inhibitors: Captopril, Enalapril, Lisinopril, Ramipril
- ARBs: Losartan, Valsartan, Telmisartan, Candesartan
- Direct Renin Inhibitor: Aliskiren
3. Calcium Channel Blockers (CCBs)
- Dihydropyridines (DHP): Amlodipine, Nifedipine, Felodipine
- Non-DHP: Verapamil, Diltiazem
4. Beta-Blockers
- Cardioselective (β1): Atenolol, Metoprolol, Bisoprolol
- Non-selective: Propranolol, Carvedilol, Labetalol
- With vasodilatory action: Nebivolol (β1 + NO release)
5. Alpha-Blockers
- Selective α1: Prazosin, Doxazosin, Terazosin
6. Central-Acting Agents
- α2 agonists: Clonidine, Methyldopa
- Imidazoline receptor agonist: Moxonidine
7. Direct Vasodilators
- Hydralazine, Minoxidil, Diazoxide, Sodium Nitroprusside
8. Dopamine Agonist
- Fenoldopam (D1 receptor)
First-Line Drugs: ABCD Mnemonic
| Letter | Drug Class |
|---|
| A | ACE inhibitors / ARBs |
| B | Beta-blockers (NOT first-line for uncomplicated HTN now) |
| C | Calcium channel blockers |
| D | Diuretics (Thiazides) |
NEET PG Favorites: Drug-Specific High-Yield Points
Thiazide Diuretics
- MOA: Block Na+/Cl- cotransporter in distal convoluted tubule
- Side effects: Hypokalemia, Hyperglycemia, Hyperuricemia, Hyperlipidemia, Hypercalcemia
- Mnemonic for side effects: "HypoK+ HyperGUT" (Glucose, Uric acid, Triglycerides)
- Unique: Thiazides cause hypercalcemia (loop diuretics cause hypocalcemia - opposite!)
- Spironolactone side effect: Gynecomastia (it's a steroid)
ACE Inhibitors (-pril)
- MOA: Inhibit conversion of Angiotensin I → Angiotensin II by ACE
- Also inhibit bradykinin degradation → ACE inhibitor cough (dry cough, most common side effect)
- Contraindications:
- Pregnancy (teratogenic - causes fetal renal hypoplasia) - absolute CI
- Bilateral renal artery stenosis
- Hyperkalemia
- Angioedema history
- Preferred in: Diabetic nephropathy, CKD, post-MI, Heart failure with reduced EF
- Captopril: Contains sulfhydryl group - causes rash, taste loss
- First dose hypotension with Captopril
ARBs (-sartan)
- MOA: Block AT1 receptors - same benefits as ACEi but NO cough
- Same contraindications as ACEi (pregnancy, bilateral RAS)
- If patient has ACEi cough → switch to ARB
- Losartan: Also has uricosuric effect (useful in gout + HTN)
Calcium Channel Blockers
| Feature | Dihydropyridines (Amlodipine) | Non-DHP (Verapamil, Diltiazem) |
|---|
| Primary action | Peripheral vasodilation | Cardiac + vascular |
| Heart rate | Reflex tachycardia | Decrease HR |
| Use in angina | Vasospastic angina | Stable + vasospastic angina |
| CI | - | Heart block, Heart failure (Verapamil) |
| Side effects | Flushing, headache, ankle edema | Constipation (Verapamil) |
- Verapamil causes the most constipation - frequent NEET PG Q
- Amlodipine: Longest acting DHP, used in isolated systolic hypertension in elderly
- Nifedipine: Short acting - reflex tachycardia, NOT used in acute MI
Beta-Blockers
- MOA: Block β1 receptors → ↓HR, ↓contractility, ↓renin release
- Non-selective BB contraindicated in asthma (block β2 → bronchospasm)
- Carvedilol = α1 + β1 + β2 blocker (used in heart failure)
- Labetalol = α1 + β blocker (drug of choice in hypertension in pregnancy and hypertensive emergency in pregnancy)
- Nebivolol = β1 blocker + releases nitric oxide (NO) → vasodilation
- Atenolol: Most cardioselective, does NOT cross BBB
Methyldopa
- MOA: Central α2 agonist → reduces sympathetic outflow
- Drug of choice in hypertension in pregnancy (along with Labetalol)
- Side effects: Sedation, dry mouth, +ve Coombs test, hemolytic anemia
Clonidine
- Central α2 agonist
- Clonidine withdrawal causes rebound hypertension (hypertensive crisis)
- Used in opioid withdrawal, ADHD, Tourette's
Hydralazine
- Direct arteriolar vasodilator
- Causes reflex tachycardia → used with beta-blocker
- Drug of choice in hypertensive emergency in pregnancy (IV form)
- Causes lupus-like syndrome (SLE-like) - NEET PG favorite!
- Mechanism: Increases cGMP → smooth muscle relaxation
Minoxidil
- Opens K+ channels → hyperpolarization → vasodilation
- Side effect: Hirsutism (used topically for hair loss - Rogaine!)
- Causes reflex tachycardia and sodium retention
Sodium Nitroprusside
- Releases NO (nitric oxide) → dilates both arteries AND veins
- Drug of choice in most hypertensive emergencies (except pregnancy)
- Toxic metabolite: Cyanide (thiocyanate toxicity with prolonged use)
- Antidote for cyanide toxicity: Sodium thiosulfate
- Must be protected from light (wrap in foil)
Fenoldopam
- D1 receptor agonist - renal vasodilator
- Preferred in hypertensive emergency with renal impairment
- Increases renal blood flow, natriuresis
Preferred Drug in Special Conditions (NEET PG Favorite!)
| Condition | Preferred Drug |
|---|
| HTN in Pregnancy | Methyldopa, Labetalol, Hydralazine (IV for emergency) |
| HTN + Diabetes/CKD | ACE inhibitor or ARB (renoprotective) |
| HTN + Heart Failure (HFrEF) | ACEi/ARB + BB (Carvedilol/Metoprolol) + Spironolactone |
| HTN + Stable Angina | BB + CCB (amlodipine) |
| HTN + Isolated systolic (elderly) | Thiazide or Amlodipine |
| HTN + Benign Prostatic Hyperplasia | α-blocker (Prazosin, Tamsulosin) |
| HTN + Pheochromocytoma | Phenoxybenzamine first (then BB) - never BB alone first! |
| HTN + Migraine prophylaxis | Propranolol |
| HTN + Gout | Losartan (uricosuric) - avoid thiazides |
| HTN + Hyperthyroidism | Propranolol |
| Resistant HTN | Add Spironolactone (MRA) |
Hypertensive Emergency vs Urgency
| Feature | Emergency | Urgency |
|---|
| BP | SBP >180 or DBP >120 | Same BP range |
| Target organ damage | YES (stroke, MI, AKI) | NO |
| Treatment | IV drugs, ICU | Oral drugs, outpatient |
| BP reduction rate | 25% in first hour | Over 24-48 hours |
IV drugs used in hypertensive emergency:
- Sodium nitroprusside (drug of choice - most emergencies)
- Labetalol (preferred in pregnancy, aortic dissection)
- Nicardipine / Clevidipine (CCB - safe, titratable)
- Nitroglycerin (preferred in acute coronary syndrome)
- Fenoldopam (renal failure)
- Esmolol (aortic dissection, perioperative)
- Hydralazine (pregnancy)
- Phentolamine (pheochromocytoma crisis)
Key NEET PG One-Liners
- Cough with ACEi → switch to ARB
- Lupus-like syndrome → Hydralazine (also Procainamide, Isoniazid)
- Cyanide toxicity → Nitroprusside (antidote: Na thiosulfate)
- Gynecomastia → Spironolactone
- Hirsutism → Minoxidil
- Rebound HTN on stopping → Clonidine
- +ve Coombs test → Methyldopa
- Beta-blocker first line in pheochromocytoma → WRONG - use alpha-blocker FIRST
- Verapamil - most constipating antihypertensive
- Amlodipine - drug of choice in isolated systolic hypertension of elderly
- Labetalol + Hydralazine - safe in pregnancy emergencies
- Nebivolol - only BB that releases NO
- Losartan - ARB with uricosuric effect
- Fenoldopam - only antihypertensive that increases renal blood flow
Sources: Lippincott Illustrated Reviews Pharmacology, Katzung's Basic & Clinical Pharmacology 16E
Want me to make MCQ-style practice questions on this topic, or go deeper into any specific drug class?