RESUMO
Drug-drug interactions are most commonly occurring phenomenon in clinical practice. Many physicians are afraid of being involved in an allegation of malpractices due to the occurrence of any severe interaction. These interactions not only occur between drugs but also between any kind of food, tobacco smoke, caffeine and alcohol etc. Therefore, the present study was directed to inspect the effect of caffeine on the anticoagulation activity of warfarin in healthy adult male albino rabbits. Blank blood samples were collected from each rabbit. Rabbits were given warfarin [0.5mg kg-1] orally via stomach tube and blood samples were collected in PT/INR vials at various intervals. After a washout period of 14 days, warfarin was orally administrated at same dose rate along with caffeine [5 mg kg-1 every twelve hours for three days] and same sampling schedule was repeated. Prothrombin time [PT] and the international normalized ratio [INR] of blood samples were determined to estimate changes in the anticoagulation activity of warfarin after its concurrent administration with caffeine. The PT data revealed that Rmax and AUC increased significantly [P