ICU · pharmacology

ICU Antihypertensive Drugs — Comprehensive

Also known as IV antihypertensives · Hypertensive emergency drugs · Labetalol · Nicardipine · Sodium nitroprusside · Clevidipine · Esmolol · Hydralazine · Phentolamine · Fenoldopam · Cyanide toxicity · Unopposed alpha stimulation

IV antihypertensives for the ICU — the nine agents every intensivist must master: LABETALOL (combined alpha+beta blocker — versatile first-line for most hypertensive emergencies; 20 mg IV bolus then 40 mg and 80 mg boluses to a 300 mg maximum in trial protocols; contraindicated in severe asthma/heart block), NICARDIPINE (dihydropyridine CCB — smooth titratable infusion 5-15 mg/h — ideal for most HTN emergencies including stroke), HYDRALAZINE (direct arteriolar vasodilator — pregnancy/pre-eclampsia favourite; 5 mg slow IV bolus repeatable; CAUTION reflex tachycardia), SODIUM NITROPRUSSIDE (arteriolar + venous NO donor — most potent — CYANIDE TOXICITY risk rises with infusion rate, cumulative dose or prolonged infusion — now largely superseded), NITROGLYCERIN (venous arteriolar NO donor — start 5 mcg/min titrating by 5 mcg/min — for ACS/acute pulmonary oedema; tachyphylaxis), CLEVIDIPINE (ultra-short DHP CCB — 1 min half-life — esterase-metabolised; VELOCITY trial: 2 mg/h start, doubled every 3 min to 32 mg/h), ESMOLOL (beta-1 selective — 500 mcg/kg load then up to 100 mcg/kg/min — aortic dissection, tachyarrhythmia), FENOLDOPAM (D1 agonist — 0.1 mcg/kg/min start — 'renal protective' claim unproven), PHENTOLAMINE (non-selective alpha-blocker — 5 mg IV bolus — pheochromocytoma crisis FIRST). Oral agents for chronic ICU BP control (ACEi/ARB, CCB, beta-blockers, diuretics, alpha-blockers). Scenario-specific rules that MUST be memorised: AORTIC DISSECTION = beta-blocker FIRST then vasodilator (prevent reflex tachycardia → propagation; target HR <60, SBP <120); HYPERTENSIVE ENCEPHALOPATHY = labetalol or nicardipine (BP down ~10% first hour, another ~15% over 2-3 h); PRE-ECLAMPSIA = hydralazine or labetalol + magnesium sulphate; PHEOCHROMOCYTOMA = phentolamine FIRST then beta-blocker (alpha before beta); COCAINE = benzodiazepines FIRST (avoid beta-blockers — unopposed alpha).

Checked against its sources on 3 Sept 2026