Adults

Initial dose is usually 50 mg once daily. Dosage may be adjusted from 25 mg to 100 mg once daily based on blood pressure response. For 25 mg, it may be used as a starting dose for certain patients or for specific indications.

Elderly

No initial dosage adjustment required. However, consider a lower starting dose (e.g., 25 mg) for elderly patients, especially those with potential volume depletion or hepatic impairment.

Renal_impairment

No initial dosage adjustment required for mild to moderate renal impairment. For severe renal impairment or patients on dialysis, a lower starting dose (e.g., 25 mg) may be considered.

Onset

Within 1 hour, peak effect at 6 hours.

Excretion

Approximately 35% excreted in urine and 60% in feces, as unchanged drug and metabolites.

Half life

Losartan: 2 hours; Active metabolite (E-3174): 6-9 hours.

Absorption

Well absorbed orally, undergoes significant first-pass metabolism. Bioavailability is approximately 33%.

Metabolism

Extensive hepatic metabolism, primarily by CYP2C9 and CYP3A4 to an active carboxylic acid metabolite (E-3174).

Lithium

Increased serum lithium concentrations and toxicity.

NSAIDs (Nonsteroidal Anti-inflammatory Drugs)

May reduce the antihypertensive effect and increase the risk of renal impairment.

Potassium-sparing diuretics/Potassium supplements

May lead to hyperkalemia (high potassium levels).