clonidine

drug

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 24, 2026

Quick Summary

Clonidine is an antihypertensive drug used to treat high blood pressure. It is also prescribed to prevent migraine headaches and to help manage withdrawal symptoms from opioids and nicotine.1

Clonidine belongs to a class of drugs known as adrenergic drugs, which affect the sympathetic nervous system. Specifically, it acts as a centrally acting sympatholytic agent by stimulating alpha-2 adrenoceptors in the brain. This stimulation reduces sympathetic activity, leading to vasodilation and a decrease in blood pressure. While effective orally or via a patch for lowering blood pressure, intravenous administration can paradoxically cause a rapid increase.2

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

cardiovascular drug
Drugs affecting the blood vessels
…of hypertension include methyldopa and clonidine, which work at the level of the central nervous system; adrenoceptor-blocking drugs (e.g., propranolol, which lowers blood pressure by reducing the cardiac output, and prazosin, which blocks the vasoconstrictor action of norepinephrine); calcium channel blockers (e.g., nifedipine); and nitrates (e.g., nitroglycerin tablets). Hypotensive drugs,…
Read More
…of hypertension include methyldopa and clonidine, which work at the level of the central nervous system; adrenoceptor-blocking drugs (e.g., propranolol, which lowers blood pressure by reducing the cardiac output, and prazosin, which blocks the vasoconstrictor action of norepinephrine); calcium channel blockers (e.g., nifedipine); and nitrates (e.g., nitroglycerin tablets). Hypotensive drugs,…
Read More

Tourette syndrome
clonidine are also effective in reducing the frequency and intensity of tics.
Read More
clonidine are also effective in reducing the frequency and intensity of tics.
Read More