Aim: To evaluate pharmacokinetic and pharmacodynamic interactions between tamsulosin and acenocoumarol.
Methods: Twelve healthy volunteers received tamsulosin 0.4 mg or placebo once daily for 9 days in a double-blind, cross-over study. On day 5 of each study period, a single 10-mg oral dose of racemic acenocoumarol was administered.
Results: The ratios (point estimates (90% confidence intervals)) of values in the presence and absence of tamsulosin were: AUCPT 1.01 (0.98, 1.03); maximum prothrombin time (Ptmax) 0.99 (0.94, 1.05); AUC (R)-acenocoumarol 1.02 (0.90, 1.16), and AUC (S)-acenocoumarol 1.03 (0.89, 1.20). Both combinations, tamsulosin and placebo with acenocoumarol, were well-tolerated.
Conclusions: Multiple doses of tamsulosin had no effect on the pharmacokinetics or pharmacodynamics of a single high dose of acenocoumarol.