DRUGS THAT DECREASE RENAL CALCIUM EXCRETION, EG, THIAZIDE DIURETICS, MAY INCREASE THE RISK OF HYPERCALCEMIA. KNOWN INTERACTION BETWEEN ANTIESTROGENIC COMPOUNDS OF THE TRIPHENYLETHYLENE DERIVATIVE CLASS AND COUMARIN-TYPE ANTICOAGULANTS (EG, WARFARIN), LEADING TO AN INCREASED PROTHROMBIN TIME. CYTOCHROME P450 3A4 ENZYME INDUCERS, SUCH AS PHENOBARBITAL, PHENYTOIN, AND CARBAMAZEPINE INCREASE THE RATE OF TOREMIFENE METABOLISM. METABOLISM OF TOREMIFENE MAY BE INHIBITED BY DRUGS KNOWN TO INHIBIT THE CYP3A4-6 ENZYMES, LIKE KETOCONAZOLE.