Clopidogrel requires CYP450-mediated hepatic metabolism to form its active metabolite (clopi-H4). This randomized, placebo-controlled, crossover study was designed to characterize the effect of a high-fat or standard breakfast on adenosine diphosphate (ADP)-induced platelet aggregation and exposure to unchanged clopidogrel and clopi-H4 following clopidogrel (300-mg loading dose, 75 mg/d for 4 days) in 72 healthy men. At day 5 and as assessed by liquid chromatography-tandem mass spectrometry, unchanged clopidogrel area under the concentration- time curve from 0 to 24 hours (AUC(0-24)) increased 3.32-fold (90% confidence interval [CI], 2.88-3.84), and clopi-H4 AUC(0-24) decreased nonsignificantly by 12% (90% CI, 0.82-0.94) upon administration of clopidogrel with a standard breakfast. The estimated treatment difference in maximum platelet aggregation (MPA) induced by ADP 5 µM and assessed by light transmission aggregometry was 4.7%, with the 90% CI (0.9%-8.5%) contained within the prespecified equipotency range of ±15%. The mean ± standard deviation of day 5 inhibition of platelet aggregation was 49.7% ± 17.2% and 54.0% ± 13.3% in the fed and fasted states, respectively. Despite increased unchanged clopidogrel and slightly decreased clopi-H4 exposure following clopidogrel administration, the numerical increase in MPA in the fed versus fasted state was small and within the prespecified limit of equipotency. These findings confirm that clopidogrel can be taken with or without food.
Trial registration: ClinicalTrials.gov NCT01129271.