Pharmacology: Clonidine
Vu H. Phan, D.C., QME, L.Ac
Hardin Simmons University
Patty Hanks Shelton School of Nursing
Pharmacology for Nursing
Heather Flores, RN, MSN
November 30th, 2009
Clonidine is a centrally acting alpha 2 agonist. Clonidine is approved to treat hypertension and relief severe pain. Clonidine has minimal adverse effects. It is both safe and effective. (Lehne, R, 2010)
Mechanism of Antihypertensive Action:
Clonidine is a centrally acting alpha 2 adrenergic agonist that causes selective activation of alpha 2 receptors in the CNS –specifically the brainstems areas associated with autonomic regulation of the cardiovascular system. By activating centrally alpha 2 receptors, clonidine reduces sympathetic outflow of blood vessels and the heart. (Lehne, R, 2010) (Abo-Zena, R., 2000)(Skidmore-Roth, L., 2009)
Mechanism of Pain Relief:
Clonidine relieve pain by binding to presynaptic and postsynaptic alpha 2 receptors in the spinal cord The result is blockade of nerve traffic in pathways that transmit pain signals from the periphery to the brain. (Wright, D., 2008)
Pharmacologic effects:
The most significant effects of clonidine occur in the heart and vascular system. By suppressing the firing of sympathetic vascular system. By suppressing the firing of sympathetic nerves to the heart, clonidine can cause bradycardia and a decrease in cardiac output. By suppressing sympathetic regulation of blood vessels, the drug promotes dilation. The net result of cardiac suppression and vasodilation is decreased blood pressure. Blood pressure is reduced in both supine and standing subjects. Because the hypotensive effects of clonidine are not posture dependent, orthostatic hypotension is minimal. (Lehne, R, 2010) (Wright, D., 2008)
Pharmacokinetics:
Clonidine is very lipid soluble. As a result, the drug is readily absorbed following oral administration and is widely distributed throughout the body including...