Tozam Drug Interactions

Losartan Potassium: Losartan potassium administered for 12 days, did not affect the pharmacokinetics or pharmacodynamics of a single dose of warfarin. Losartan potassium did not affect the pharmacokinetics of oral or intravenous digoxin. Co-administration of Losartan and Cimetidine led to an increase of about 18% in AUC of Losartan Potassium but did not affect the pharmacokinetics of E-3174. Co-administration of Losartan potassium and phenobarbital led to reduction of about 20% in the AUC of Losartan potassium and E-3174. There is no pharmacokinetic interaction between Losartan potassium and hydrochlorothiazide.
Inhibitors of Cytochrome P3A4 are unlikely to have significant drug interactions while potent inducers of Cytochrome P3A4 might cause a significant interaction.
As with other drugs that block angiotensin II or its side effects, concomitant use of potassium-sparing diuretics (e.g. Spironolactone, triamterene, amiloride), potassium supplements, or salt substitutes containing potassium may lead to an increase in serum potassium.
Amlodipine Besilate: Amlodipine besilate has been safely administered with thiazide diuretics, beta adrenoreceptor blocking drugs, angiotensin converting enzyme inhibitors, long acting nitrates, sublingual glyceryl trinitrate, nonsteroidal anti-inflammatory drugs, antibiotics and oral hypoglycemic agents.
Co-administration of amlodipine besilate with digoxin did not change serum digoxin levels or digoxin renal clearance in normal volunteers. Co-administration of cimetidine did not alter the pharmacokinetics of amlodipine.
In healthy volunteers, co-administration of amlodipine besilate did not significantly alter the effect of warfarin on prothrombin time. The introduction of amlodipine besilate is not likely to result in the need for modification of an established warfarin regimen.