indication

For management of High blood pressure

pharmacology

Guanabenz, a centrally acting α-2 adrenergic agonist, is indicated for treatment of hypertension.

mechanism of action

Guanabenz's antihypertensive effect is thought to be due to central alpha-adrenergic stimulation, which results in a decreased sympathetic outflow to the heart, kidneys, and peripheral vasculature in addition to a decreased systolic and diastolic blood pressure and a slight slowing of pulse rate. Chronic administration of guanabenz also causes a decrease in peripheral vascular resistance.

toxicity

Excessive contraction of the pupils, irritability, low blood pressure, sleepiness, slow heartbeat, sluggishness

biotransformation

Hepatic

absorption

Approximately 75% absorbed from gastrointestinal tract

half life

6 hours.

drug interactions

Thiabendazole: The strong CYP1A2 inhibitor, Thiabendazole, may increase the effects and toxicity of Guanabenz by decreasing Guanabenz metabolism and clearance. Monitor for changes in the therapeutic and adverse effects of Guanabenz if Thiabendazole is initiated, discontinued or dose changed.

Treprostinil: Additive hypotensive effect. Monitor antihypertensive therapy during concomitant use.

Trimipramine: Trimipramine may reduce the antihypertensive effect of the alpha2-agonist, Guanabenz. Trimipramine may also increase the rebound hypertensive effect of Clonidine. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Clonidine if Trimipramine is initiated, discontinued or dose changed. Guanabenz should be withdrawn very gradually to reduce the risk of hypertensive crisis.