Information last reviewed: May 2026 — for educational purposes only.
Clonidine is a centrally acting alpha-2 adrenergic agonist available under the brand name Catapres. It reduces blood pressure by stimulating alpha-2 receptors in the brainstem, which decreases sympathetic outflow to the heart and blood vessels. It is a prescription medication used for hypertension and a growing range of off-label indications.
Uses of Clonidine
Clonidine is primarily prescribed for hypertension when other agents are not tolerated or sufficient. Off-label uses include treatment of ADHD (the extended-release form Kapvay is FDA-approved for ADHD), PTSD-associated nightmares, opioid and nicotine withdrawal management, alcohol withdrawal support, and relief of menopausal hot flushes. Its versatility makes it a useful adjunct in several clinical settings.
Mechanism, Warnings, and Key Interactions
By activating presynaptic and postsynaptic alpha-2 receptors in the central nervous system, clonidine reduces norepinephrine release and lowers heart rate and vascular resistance. Sedation and dry mouth are the most frequently reported side effects. Bradycardia and orthostatic hypotension are clinically significant adverse effects that warrant monitoring. The most critical safety concern is rebound hypertension upon abrupt discontinuation — blood pressure can rise sharply, sometimes to dangerously high levels. Patients, especially those on higher doses or concurrently taking beta-blockers, must taper the dose gradually under medical supervision. Beta-blockers also worsen clonidine-induced rebound when stopped simultaneously. Additive CNS depression occurs with sedatives, alcohol, and other central depressants. Regarding the transdermal patch: patients must remove the patch before entering an MRI scanner, as the metallic content can cause skin burns.
Available Strengths and Formulations
Catapres oral tablets are available in 0.1 mg, 0.2 mg, and 0.3 mg strengths, typically dosed two to three times daily. The Catapres-TTS transdermal patch system delivers 0.1 mg/day (TTS-1), 0.2 mg/day (TTS-2), or 0.3 mg/day (TTS-3) over a seven-day application period. The patch provides more consistent blood levels and improved convenience for patients who have difficulty adhering to multiple daily oral doses.
Pricing Overview
Generic clonidine tablets are among the most affordable antihypertensive medications. The oral tablet form carries a low generic cost, often under $10–$15 per month at most pharmacies. The transdermal patch, particularly branded Catapres-TTS, is considerably more expensive. Contact Lucas Clinic for current pricing and availability options.
Frequently Asked Questions
Why must clonidine never be stopped suddenly?
Abrupt discontinuation causes rebound hypertension — a potentially dangerous surge in blood pressure resulting from the sudden removal of central sympathetic suppression. Symptoms can include severe headache, agitation, and elevated heart rate. Always taper the dose gradually, and if also taking a beta-blocker, the clonidine should be tapered before stopping the beta-blocker to avoid compounding the rebound effect.
Is the clonidine patch interchangeable with the tablets?
The transdermal patch and oral tablets are not directly interchangeable on a dose-for-dose basis. The patch delivers medication continuously over seven days, providing stable plasma levels, while tablets require multiple daily doses and produce peak-and-trough fluctuations. Switching between formulations should be done under medical supervision with appropriate dosage adjustment.
Can clonidine be used for conditions other than high blood pressure?
Yes. Clonidine has a broad range of off-label uses supported by clinical evidence, including ADHD in children and adults, PTSD-related nightmares, mitigation of opioid and alcohol withdrawal symptoms, nicotine dependence support, and management of menopausal hot flushes. Discuss these uses with a qualified clinician to determine appropriateness for your situation.
Disclaimer: This page is for general informational purposes only and does not constitute medical advice. Always consult a licensed healthcare professional before taking any medication. See our full disclaimer.