The Sound of Evolution
Clonidine
Mechanism of action:
Clonidine is an imidazoline derivative. Clonidine can cross the blood-brain barrier and selectively stimulates α2-adrenergic receptors in the vasomotor center of the medulla, thereby inhibiting the release of norepinephrine and reducing central sympathetic outflow. This slows the heart rate, decreases cardiac output, lowers peripheral vascular resistance, and ultimately reduces blood pressure. Clonidine also acts on imidazoline I1 receptors in the medulla, which likewise suppress sympathetic activity and lower blood pressure.
Reference(s):
1. Hossmann V et al. (1980). Sedative and cardiovascular effects of clonidine and nitrazepam. Clin Pharmacol Ther.
2. Khan ZP et al. (1999). Alpha-2 and imidazoline receptor agonists: Their pharmacology and therapeutic role. Anaesthesia.
3. Sjoberg RJ et al. (1992). The clonidine suppression test for pheochromocytoma: A review of its utility and pitfalls. Arch Intern Med.