Drug Groups

approved

Description

An antihypertensive agent that acts by inhibiting selectively transmission in post-ganglionic adrenergic nerves. It is believed to act mainly by preventing the release of norepinephrine at nerve endings and causes depletion of norepinephrine in peripheral sympathetic nerve terminals as well as in tissues. [PubChem]

Indication

For the treatment of moderate and severe hypertension, either alone or as an adjunct, and for the treatment of renal hypertension.

Pharmacology

High blood pressure can cause the heart and arteries to not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled. Guanethidine works by decreasing the heart rate and relaxing the blood vessels so that blood can flow more easily through the body, thereby reducing these risks. It is a postganglionic sympathetic nerve terminal blocker that prevents the release of norepinephrine from nerve terminals.

Toxicity

Side effects include drowsiness, dizziness, tiredness or confusion. LD₅₀=1000 mg/kg (mouse, oral)

Affected Organisms

Biotransformation

Guanethidine is converted by the liver to three metabolites, which are excreted in the urine. The metabolites are pharmacologically less active than the parent compound.

Absorption

3-30% of oral dose (poor and highly variable)

Half Life

1.5 days

Elimination

Ismelin is converted by the liver to three metabolites, which are excreted in the urine.

Clearance

* Renal cl=56 ml/min

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