Clonidine

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** An imidazoline derivate and centrally-acting alpha-adrenergic agonist, with antihypertensive activity. Clonidine binds to and stimulates central alpha-2 adrenergic receptors, thereby reducing the amount of norepinephrine (NE) release and thus decreasing sympathetic outflow to the heart, kidneys, and peripheral vasculature. The reduction in sympathetic outflow leads to decreased peripheral vascular resistance, decreased blood pressure, and decreased heart rate. In addition, clonidine binds to imidazoline receptor subtype 1 (I1), which may also contribute to a reduction in blood pressure.

**Synonyms:** - CLONIDINE - Catapres-TTS - N-(2,6-Dichlorophenyl)-4,5-dihydro-1H-imidazol-2-amine - N-(2,6-Dichlorophenyl)-4,5-dihydro-1H-imidazol-2-amine - clonidine