Drug Groups

approved; investigational

Description

Olmesartan is an antihypertensive agent which belongs to the class of medicines called angiotensin II receptor antagonists. It acts rapidly to lower high blood pressure. It is marketed worldwide by Daiichi Sankyo, Ltd. and in the United States by Daiichi Sankyo, Inc. and Forest Laboratories.

Indication

For the treatment of hypertension.

Pharmacology

Olmesartan, a specific angiotensin II type 1 antagonist, is used alone or with other antihypertensive agents to treat hypertension. Unlike the angiotensin receptor antagonist losartan, olmesartan does not have an active metabolite or possess uricosuric effects. Blockade of the angiotensin II receptor inhibits the negative regulatory feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and circulating angiotensin II levels do not overcome the effect of olmesartan on blood pressure.

Toxicity

Symptoms of overdose include dehydration (dry mouth, excessive thirst, muscle pain or cramps, nausea and vomiting, weakness), dizziness, low blood pressure, and slow or irregular heartbeat.

Affected Organisms

Biotransformation

Olmesartan is rapidly and completely bioactivated by ester hydrolysis to olmesartan during absorption from the gastrointestinal tract. There is virtually no further metabolism of olmesartan.

Absorption

Bioavailability is about 26%. Food does not affect the bioavailability of olmesartan.

Half Life

Approximately 13 hours

Protein Binding

Highly bound to plasma proteins (99%) and does not penetrate red blood cells.

Distribution

* 17 L

Clearance

* Total plasma cl=1.3 L/h
* Renal cl=0.6 L/h

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