Impact of proton pump inhibitors or famotidine on the antiplatelet actions during dual-antiplatelet therapy in Japanese patients.

It has been reported that the antiplatelet action becomes attenuated when a proton pump inhibitor is used in combination with clopidogrel. The effect of an antacid causing platelet aggregation during the administration of clopidogrel was investigated. The subjects consisted of 265 patients with coronary artery disease. Platelet aggregation function testing (light transmittance aggregometry) was conducted while aspirin and clopidogrel 75 mg were taken orally and the minimum concentration of aggregation induction platelet aggregation threshold index was measured. The ADP-PATI, measured with ADP as the inducing substance, was compared and investigated according to the type of concomitantly used antacid. The results of the ADP-PATI were: control group: 3.47 ± 0.95 μM (N = 67), famotidine group: 3.80 ± 0.52 μM (N = 32), rabeprazole group: 3.43 ± 0.93 μM (N = 87), lansoprazole group: 3.28 ± 1.04 μM (N = 63) and omeprazole group: 3.33 ± 0.81 μM (N = 16). No statistically significant difference was observed regarding the ADP-PATI of respective groups compared to the control group. The concomitant use of famotidine, rabeprazole, lansoprazole, and omeprazole did not affect the antiplatelet action of clopidogrel in Japanese patients.