ICU · Pharmacology

ICU antiarrhythmic drugs — comprehensive (Vaughan-Williams classification)

Also known as Antiarrhythmics · Vaughan-Williams classification · Class I sodium channel blockers · Class II beta-blockers · Class III potassium channel blockers · Class IV calcium channel blockers · Amiodarone · Lidocaine · Procainamide · Flecainide · Adenosine · Digoxin

Antiarrhythmic drugs classified by the Vaughan-Williams system: Class I (sodium channel blockers — Ia quinidine/procainamide [prolong AP + QT], Ib lidocaine/phenytoin [shorten AP, ischaemic-tissue selectivity], Ic flecainide [markedly slow conduction, AVOID in structural heart disease — CAST]); Class II (beta-blockers — metoprolol/esmolol/bisoprolol — reduce sympathetic drive, slow AV node); Class III (potassium channel blockers — amiodarone [MOST effective ICU antiarrhythmic, broad-spectrum multichannel but long half-life (50 to 60 days) + pulmonary/hepatic/thyroid toxicity], sotalol [also beta-blocker], ibutilide, dronedarone); Class IV (calcium channel blockers — verapamil/diltiazem — AV node only, non-dihydropyridine). Other: adenosine [AV node reentry — terminates SVT 6mg then 12mg rapid IV push, brief asystole], digoxin [vagomimetic — rate control AF in heart failure], magnesium [torsades — IV]. Clinical applications: AF (rate control = beta-blocker/diltiazem/digoxin; rhythm = amiodarone/flecainide), VT (amiodarone 300mg IV then infusion; lidocaine for ischaemic VT), SVT (adenosine first-line), torsades (magnesium 2g IV).

Checked against its sources on 2 Sept 2026