Drug Groups

approved; investigational

Description

A centrally acting antihypertensive agent. The drug lowers both systolic and diastolic blood pressure by activating the central nervous system alpha-2 adrenoreceptors, which results in reduced sympathetic outflow leading to reduced vascular tone. Its adverse reactions include dry mouth, sedation, and constipation. [PubChem]

Indication

For use alone or in combination with other classes of antihypertensive agents in the management of hypertension. Has also been used for the treatment of attention deficit hyperactivity disorder (ADHD) in pediatric patients.

Pharmacology

Guanfacine is a phenylacetyl-guanidine derivative hypotensive and a centrally-acting, alpha(2)-adrenergic receptor agonist used alone or in combination with other drugs for the treatment of hypertension.

Toxicity

Symptoms of overdose include drowsiness, lethargy, bradycardia and hypotension. LD₅₀=165mg/kg (orally in mice)

Affected Organisms

Biotransformation

Hepatic

Absorption

Rapid and complete, with an oral bioavailability of approximately 80%.

Half Life

17 hours (range 10-30 hours)

Protein Binding

Approximately 70% bound to plasma proteins, independent of drug concentration.

Elimination

In individuals with normal renal function, guanfacine and its metabolites are excreted primarily in the urine.

Distribution

* 6.3 L/kg

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