AMPICILLIN AND AMOXICILLIN --PEAK CONCENTRATIONS OF RALOXIFENE AND THE OVERALL EXTENT OF ABSORPTION ARE REDUCED 28% AND 14%, RESPECTIVELY, WITH CO-ADMINISTRATION OF AMPICILLIN & AMOXYCILLIN. HOWEVER, THE SYSTEMIC EXPOSURE AND THE ELIMINATION RATE OF RALOXIFENE WERE NOT AFFECTED. ANTACIDS --CONCURRENT ADMINISTRATION OF CALCIUM CARBONATE OR ALUMINUM AND MAGNESIUM HYDROXIDE-CONTAINING ANTACIDS DOES NOT AFFECT THE SYSTEMIC EXPOSURE OF RALOXIFENE.
CORTICOSTEROIDS --THE CHRONIC ADMINISTRATION OF RALOXIFENE IN POSTMENOPAUSAL WOMEN HAS NO EFFECT ON THE PHARMACOKINETICS OF METHYLPREDNISOLONE GIVEN AS A SINGLE ORAL DOSE. CHOLESTYRAMINE, AN ANION EXCHANGE RESIN, CAUSES A 60% REDUCTION IN THE ABSORPTION AND ENTEROHEPATIC CYCLING OF RALOXIFENE AFTER A SINGLE DOSE. RALOXIFENE HAD NO EFFECT ON THE PHARMACOKINETICS OF WARFARIN. HOWEVER, A 10% DECREASE IN PROTHROMBIN TIME WAS OBSERVED IN THE SINGLE-DOSE STUDY. IF ESTROACT IS GIVEN CONCURRENTLY WITH WARFARIN OR OTHER COUMARIN DERIVATIVES, PROTHROMBIN TIME SHOULD BE MONITORED MORE CLOSELY WHEN STARTING OR STOPPING THERAPY WITH RALOXIFENE. IN VITRO, RALOXIFENE DID NOT INTERACT WITH THE BINDING OF PHENYTOIN, TAMOXIFEN.