Cozaar - General Information

An antagonist of angiotensin type 1 receptor with antihypertensive activity due to the reduced pressor effect of angiotensin II. [PubChem]


Pharmacology of Cozaar

Cozaar is the first of a class of antihypertensive agents called angiotensin II (AG II) receptor antagonists. It is, along with its longer acting active metabolite (E-3174), a specific and selective AT1 receptor antagonist. Cozaar blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the AT1 receptor found in many tissues, (e.g., vascular smooth muscle, adrenal gland).


Cozaar for patients


Losartan potassium is used to treat high blood pressure. It may be used alone
or with other medications for high blood pressure. This medication should,
generally, not be used during pregnancy. If you are pregnant or considering
becoming pregnant, inform your physician immediately to discuss the risks
versus benefits. There are few side effects associated with losartan potassium.
Those most frequently reported, cough, upper respiratory infection and
dizziness, occurred no more frequently than in patients who did not take this
medication. You may take this medication with or without food. You should have
your blood pressure checked regularl.


Cozaar Interactions

No significant drug-drug pharmacokinetic interactions have been found in interaction studies with hydrochlorothiazide, digoxin, warfarin, cimetidine and phenobarbital. Rifampin, an inducer of drug metabolism, decreased the concentrations of losartan and its active metabolite. In humans, two inhibitors of P450 3A4 have been studied. Ketoconazole did not affect the conversion of losartan to the active metabolite after intravenous administration of losartan, and erythromycin had no clinically significant effect after oral administration. Fluconazole, an inhibitor of P450 2C9, decreased active metabolite concentration and increased losartan concentration. The pharmacodynamic consequences of concomitant use of losartan and inhibitors of P450 2C9 have not been examined. Subjects who do not metabolize losartan to active metabolite have been shown to have a specific, rare defect in cytochrome P450 2C9. These data suggest that the conversion of losartan to its active metabolite is mediated primarily by P450 2C9 and not P450 3A4.

As with other drugs that block angiotensin II or its effects, concomitant use of potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, or salt substitutes containing potassium may lead to increases in serum potassium.

As with other antihypertensive agents, the antihypertensive effect of losartan may be blunted by the non-steroidal anti-inflammatory drug indomethacin.


Cozaar Contraindications

COZAAR is contraindicated in patients who are hypersensitive to any component of this product.


Additional information about Cozaar

Cozaar Indication: For the treatment of hypertension.
Mechanism Of Action: Cozaar and its longer acting active metabolite (E-3174) interfere with the binding of angiotensin II to the angiotensin II AT1-receptor by, themselves, binding reversibly to the receptors in vascular smooth muscle and the adrenal gland. As angiotensin II is a vasoconstrictor, which also stimulates the synthesis and release of aldosterone, blockage of its effects results in decreases in systemic vascular resistance. Neither Cozaar or its metabolite inhibit the angiotensin converting enzyme, other hormone receptors, or ion channels.
Drug Interactions: Amiloride Increased risk of hyperkaliemia
Drospirenone Increased risk of hyperkaliemia
Potassium Increased risk of hyperkaliemia
Spironolactone Increased risk of hyperkaliemia
Triamterene Increased risk of hyperkaliemia
Indomethacin Indomethacin decreases the effect of losartan
Lithium Cozaar increases serum levels of lithium
Rifampin Rifampin decreases the effect of losartan
Food Interactions: Take without regard to meals. Take at same time each day. Food delays absorption, but does not affect the extent of absorption.
Generic Name: Losartan
Synonyms: Not Available
Drug Category: Antihypertensive Agents; Antiarrhythmic Agents; Angiotensin II Receptor Antagonists
Drug Type: Small Molecule; Approved

Other Brand Names containing Losartan: Cozaar; DUP 89; Hyzaar; Lacidipine; Lortaan;
Absorption: Well absorbed, the systemic bioavailability of losartan is approximately 33%
Toxicity (Overdose): Hypotension and tachycardia; Bradycardia could occur from parasympathetic (vagal) stimulation, LD50= 1000 mg/kg (orally in rat)
Protein Binding: 99.7%
Biotransformation: Hepatic. Oxidation of the 5-hydroxymethyl group on the imidazole ring results in the active metabolite of losartan.
Half Life: 2 hours
Dosage Forms of Cozaar: Tablet Oral
Chemical IUPAC Name: [2-butyl-5-chloro-3-[[4-[2-(2H-tetrazol-5-yl)phenyl]phenyl]methyl]imidazol-4-yl]methanol
Chemical Formula: C22H23ClN6O
Losartan on Wikipedia:
Organisms Affected: Humans and other mammals