In clinical pharmacokinetic trials, no drug interactions of clinical significance have been identified with hydrochlorothiazide, digoxin, warfarin, cimetidine, phenobarbital, ketoconazole, and erythromycin. Rifampin and fluconazole have been reported to reduce levels of active metabolite. The clinical consequences of these interactions have not been evaluated.
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-containing potassium may lead to increases in serum potassium.
As with other antihypertensive agents, the antihypertensive effect of losartan may be attenuated by the non-steroidal anti-inflammatory drug indomethacin.