Intravascular volume depletion: In patients who are intravascularly volume depleted (e.g. those treated with high-dose diuretics), symptomatic hypotension may occur. Such a condition should be corrected prior to administration of Losartan, or a lower starting dose should be used.
Hepatic Impairment: Based on pharmacokinetic data, which demonstrate significantly increased plasma concentrations of Losartan, or a lower starting dose should be considered for patients with history of hepatic impairment.
Renal artery stenosis: Other drugs that affect the renin-angiotensin-aldosterone system may increase blood urea and serum creatinine in patients with bilateral renal artery stenosis or stenosis of the artery to a solitary kidney. While not confirmed, this potentially may occur with angiotensin-II receptor antagonists.
Use in Pregnancy: Although there is no experience with the use of Losartan in pregnant women, animal studies with Losartan have demonstrated foetal and neonatal injury and death, the mechanism of which is believed to be its effects on the renin-angiotensin-aldosterone system. In humans, foetal renal perfusion, which is dependent upon the development of the renin-angiotensin-aldosterone system, begins in the second trimester.
When used in pregnancy during the second trimesters, drugs that act directly on the renin-angiotensin-aldosterone system, begins can cause injury and even death in the developing foetus. Losartan is contraindicated in pregnancy, and if pregnancy is detected, Losartan should be discontinued immediately.
Use in Lactation: It is not known whether Losartan is excreted in human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made whether to discontinue breast-feeding or discontinue the drug, taking into account the importance of the drug to the mother.
Use in Children: Safety and efficacy in children have not been established.