Losartan

Information about Losartan

Losartan_structure

Losartan is an angiotensin II receptor blocker used in the therapy of hypertension and diabetic nephropathy.

Liver safety of Losartan

Losartan is associated with a low rate of transient serum aminotransferase elevations and has been linked to rare instances of acute liver injury.

Mechanism of action of Losartan

Losartan (loe sar' tan) was the first angiotensin II receptor blocker (ARB) to be approved for use in the United States and is still widely used for therapy of hypertension. Losartan inhibits the renin-angiotensin system by blocking the angiotensin II type 1 receptor (AT1), which prevents the vasoconstriction and volume expansion induced by circulating angiotensin II and thus accounts for its antihypertensive activity.

FDA approval information for Losartan

Losartan was approved for use in the United States in 1995 and current indications include hypertension as well as prevention of progression of diabetic nephropathy, and decrease in risk of stroke in patients with hypertension and left ventricular hypertrophy.

Dosage and administration for Losartan

Losartan is available in 25, 50 and 100 mg tablets in generic forms and under the trade name Cozaar. Fixed dose combinations with hydrochlorothiazide are also available (Hyzaar and others). The typical dose of losartan in adults in 50 to 100 mg in one or two divided doses daily and it is used long term.

Side effects of Losartan

Side effects are uncommon, but can include headache, dizziness, fatigue, cough, gastrointestinal upset, and fetal toxicity. Chronic therapy with losartan has been implicated in rare instances of severe sprue-like enteropathy that typically presents after months or years of therapy with diarrhea, weight loss, and abdominal discomfort. Intestinal biopsy that shows villous fattening and atrophy, similar to celiac disease. However, the diarrhea does not improve with a gluten-free diet, but does resolve promptly with stopping the losartan. This adverse effect is most common with olmesartan.

Contraindications

Losartan should not be used in the following situations:

• Known hypersensitivity to losartan or any components of the formulation
• Pregnancy: Losartan is classified as FDA pregnancy category D and can cause fetal harm or death.
• Concomitant use of aliskiren in patients with diabetes or kidney impairment

Drug interactions

Losartan may interact with other medications, including:

• Potassium-sparing diuretics or potassium supplements: Increased risk of hyperkalemia.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): Reduced antihypertensive effect and increased risk of kidney dysfunction.
• Lithium: Increased risk of lithium toxicity.

See also

• Angiotensin II receptor antagonist
• Hypertension
• Diabetic kidney disease
• Heart failure

• Dailymed label info on Losartan
• FDA Losartan