Antihypertensive Drugs
Direct answer
The first-line classes for hypertension are ACE inhibitors or ARBs, calcium channel blockers and thiazide-type diuretics, used alone or in low-dose combination, with choice individualised by comorbidity — ACE inhibitors or ARBs for diabetes with proteinuria, and labetalol, extended-release nifedipine or methyldopa in pregnancy, where ACE inhibitors and ARBs are contraindicated. NEET-PG tests this subject mainly through drug-of-choice stems and mechanism-based adverse effects.
What you must remember
- First-line classes: ACE inhibitors/ARBs, calcium channel blockers (amlodipine-type) and thiazide-type diuretics; beta-blockers are not first-line for uncomplicated hypertension but are compelling after myocardial infarction, in heart failure and in angina.
- ACE inhibitors: cough and angio-oedema (bradykinin accumulation), hyperkalaemia and acute kidney injury risk; contraindicated in pregnancy (fetopathy) and bilateral renal artery stenosis. ARBs share efficacy and fetotoxicity with less cough.
- Dihydropyridine CCBs: amlodipine and peers cause ankle oedema, gingival hyperplasia and flushing; short-acting nifedipine causes reflex tachycardia and is avoided for chronic hypertension control.
- Non-dihydropyridine CCBs: verapamil and diltiazem cause bradycardia and constipation (verapamil classically), and combine dangerously with beta-blockers for the conducting system.
- Thiazides: hypokalaemia, hyponatraemia, hyperuricaemia (gout), hypercalcaemia and hyperglycaemia; chlorthalidone is the longer-acting, evidence-favoured option of the class.
- Special situations: pregnancy — labetalol, extended-release nifedipine or methyldopa; diabetes with proteinuria — ACE inhibitor/ARB; benign prostatic hyperplasia — alpha-1 blockers add benefit; phaeochromocytoma — alpha-blockade (phenoxybenzamine/phentolamine) established before beta-blockade, never beta-blockade alone.
- Hypertensive emergencies: intravenous labetalol, nicardipine, nitroglycerin or nitroprusside (risking cyanide toxicity with prolonged high-dose use) for controlled blood-pressure reduction.
Common confusion
Two pairs generate most errors. First, ACE inhibitors versus ARBs: both block the renin-angiotensin system and both are fetotoxic, but only ACE inhibitors raise bradykinin, so cough and angio-oedema are characteristic of that class. Second, beta-blockade in the wrong context: non-selective agents can trigger bronchospasm in asthmatics, mask hypoglycaemia awareness in diabetics, and — given before alpha-blockade in phaeochromocytoma — precipitate crisis by blocking beta-mediated vasodilation while leaving alpha-mediated vasoconstriction unopposed. Also keep emergencies and urgencies apart: emergency (target-organ damage) needs intravenous therapy in a monitored setting, while urgency usually needs oral therapy resumed, not rapid normalisation.
Exam-focused takeaway
NEET-PG questions on antihypertensives are comorbidity-matched vignettes: the single best drug for a diabetic with proteinuria, a pregnant woman, an asthmatic, a patient with coexisting angina or benign prostatic hyperplasia. A second bank of questions is mechanism-based adverse effects — ACE-inhibitor cough from bradykinin, verapamil constipation, thiazide-induced gout and hypokalaemia, amlodipine ankle oedema and gum hyperplasia. Contraindications form a third: ACE inhibitors/ARBs in pregnancy, beta-blockers in asthma and heart block, non-dihydropyridines with beta-blockers together. Emergency-management stems ask for the intravenous agent. Learn each class as mechanism, signature toxicity and matching patient — the three-part chain answers nearly every stem.
Practise previous-year and exam-style antihypertensive questions inside the PrepElephant app — topic-wise banks, full-length mocks and spaced revision that keeps drug-of-choice pairings sharp.
Frequently asked questions
Which antihypertensive classes are first-line?
ACE inhibitors or ARBs, calcium channel blockers and thiazide-type diuretics, alone or in low-dose combination, individualised to comorbidity.
Which antihypertensives are safe in pregnancy?
Labetalol, extended-release nifedipine and methyldopa; ACE inhibitors and ARBs are contraindicated because they injure the foetus.
Why do ACE inhibitors cause cough but ARBs do not?
ACE inhibition accumulates bradykinin, which stimulates airway receptors; ARBs leave bradykinin metabolism intact, so cough is far less common.
How is hypertension managed in phaeochromocytoma?
Alpha-blockade first (phenoxybenzamine or phentolamine), with beta-blockade added only after adequate alpha-blockade — never the reverse.
Why are beta-blockers not first-line for uncomplicated hypertension?
They lack the outcome advantage of the first-line classes for this indication, while retaining bronchospasm, bradycardia, masking of hypoglycaemia and fatigue — reserved for compelling indications like post-infarction care and heart failure.
Which drugs treat hypertensive emergency?
Intravenous labetalol, nicardipine, nitroglycerin or nitroprusside, titrated for a controlled reduction; prolonged use of nitroprusside risks cyanide toxicity.
Practise this in the PrepElephant app
Question banks, previous-year questions, mock tests and revision tools — for Antihypertensive Drugs and Pharmacology. Free to start.