A diabetic female on INH and rifampicin for TB suffers from deep vein thrombosis. She is staed on warfarin but her prothrombin time is not raised. What is the next best step in management of the condition?
The patient in the question is receiving rifampicin it enhance the metabolism of warfarin, as rifampicin is a microsomal enzyme inducer. Increased metabolism of warfarin results in insufficient prolongation of prothrombin time. Most effective next step in management is to increase the dose of warfarin. Since such an option is not mentioned, next suitable approach would be to use low molecular weight heparin as an anticoagulant. Ref: Essentials of Medical Pharmacology By KD Tripathi, 5th Edition, Pages 563, 700
Use LMW heparin
Long term heparin therapy
Switch ethambutol for rifampin
Replace warfarin with acesoumarin