<prompt> Which of the following drugs may enhance the effect of warfarin and increase the risk of bleeding?PhenobarbitoneKetoconazoleRifampicinCarbamazepine  <response>: DRUGS INCREASING THE EFFECT OF WARFARIN DRUGS DECREASING THE EFFECT OF WARFARIN Broad Spectrum Antibiotics Kill GI bacteria and decrease formation of Vitamin K Cephalosporins that cause hypoprothrombinemia Cefamandole, Cefoperazone Moxalactam Aspirin Microsomal Enzyme Inhibitors Erythromycin Cimetidine Ketoconazole Enzyme inducers Rifampicin Griseofulvin Phenobarbitone Oral contraceptives increase clotting factors 