Interaction between warfarin and propranolol.
The interaction between propranolol and warfarin was investigated in six healthy volunteers using a low dose warfarin protocol and in New Zealand white rabbits. Warfarin concentration (Cmin) in the volunteers increased by 14.7% on addition of propranolol (P less than 0.02). There was no significant change in prothrombin time. In the rabbit study, elimination half-life was shorter in the propranolol treated animals (8.20 +/- 0.44 h) than in controls (10.89 +/- 0.62 h). This was due to a fall in its volume of distribution from 1.13 +/- 0.10 1 kg-1 in controls to 0.81 +/- 0.08 1 kg-1 in the propranolol treated group. Clearance was not significantly altered. The small change in warfarin concentration could be of clinical importance in some patients because warfarin has a low therapeutic index. This requires further investigation.
D000328:Adult; D000818:Animals; D004347:Drug Interactions; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000494:pharmacology*; D011517:Prothrombin Time; D011817:Rabbits; D014018:Tissue Distribution; D014859:Warfarin / Q000378:metabolism / Q000494:pharmacology*
D014859:Warfarin; D011433:Propranolol