Anticoagulant effect of warfarin is increased by all of the following drugs, EXCEPT:
Phytonadione is a vitamin K preparation and is used to control bleeding caused by warfarin. The anticoagulant effects of warfarin is increased by drugs that inhibits its metabolic clearance either through stereoselective or non selective pathways. Examples of such drugs are amiodarone, phenylbutazone, sulfinpyrazone, disulfiram, metronidazole, trimethoprim sulfamethoxazole, cimetidine, omeprazole, clofibrate, anabolic steroids. Drugs which increase the metabolic clearance of warfarin are: Barbiturates Rifampicin Griseofulvin Carbamazepine Ref: Thrombosis and Hemorrhage edited by Joseph Loscalzo, page 946.
Cimetidine
Phytonadione
Amiodarone
Phenylbutazone