Clonidine

Overview

Central alpha-2 agonist that acts on the brainstem to turn off sympathetic outflow. Highly effective but fraught with severe rebound hypertension upon withdrawal.

Maximum Dose

Max 900 mcg/day (given in divided doses).

Clinical Focus

Never cease abruptly. Must be tapered over 7-10 days to avoid a fatal hypertensive crisis.

Bottom Line

Clonidine is a centrally-acting adjunct for resistant hypertension, opioid withdrawal, and ADHD, but abrupt cessation causes dangerous rebound hypertensive crises.

Brand Names

Catapres, Dixarit

Oral Routes

Tablets (100 mcg, 150 mcg), Dixarit (25 mcg). Note microgram dosing!

Parenteral

Ampoule (150 mcg/1 mL) for IV use (Rare, Specialist only).

Prescribing & PBS

Unrestricted General Benefit (S4).

Primary

Hypertension, menopausal flushing, migraine prophylaxis.

Off-Label

Withdrawal syndromes, severe acute agitation, ADHD in children.

Clinical Place

Last-line for hypertension. Highly useful in toxicology/psychiatry for hyperadrenergic states.