Purpose: To evaluate the pharmacokinetic and pharmacodynamic effects of concomitant administration of single loading doses of clopidogrel or multiple doses of clopidogrel with multiple doses of dabigatran etexilate.
Methods: This was an open-label trial in healthy male subjects. In part 1 (pilot, n = 8) and part 3 (n = 12), a single dose of clopidogrel (300 or 600 mg, respectively) was given concomitantly with dabigatran etexilate at steady state; part 2 was a randomized, multiple-dose, crossover study with the test treatment being clopidogrel at steady state [300 mg loading dose on day 1, then 75 mg once daily (qd)] with concomitant dabigatran.
Results: Bioavailability was moderately increased when a loading dose of clopidogrel (300 mg in part 1 and 600 mg in part 3) was administered concomitantly with dabigatran etexilate 150 mg twice daily (bid). Test/reference ratios for AUC(τ,ss) were 135% (90% CI 107-169%) and 132% (90% CI 112-156%), respectively. Steady-state dosing of clopidogrel 75 mg qd and dabigatran etexilate 150 mg bid (part 2) demonstrated minor effects on dabigatran pharmacokinetics (AUC(τ,ss) ratio test/reference: 91.9%, 90% CI 78.7-107%) or its pharmacokinetic/pharmacodynamic relationships (activated partial thromboplastin time, ecarin clotting time, thrombin time). Similarly, clopidogrel bioavailability remained unchanged by chronic administration of dabigatran etexilate (part 3: ratio test/reference for AUC(0-24) was 103%; 90% CI 80.3-131%), as did its pharmacodynamic effects on the inhibition of platelet aggregation.
Conclusions: When given concomitantly, dabigatran etexilate and clopidogrel at clinically relevant doses did not appear to have significant effects on the pharmacokinetic and pharmacodynamic profiles of either agent.