Original ArticleDo Proton Pump Inhibitors Attenuate the Effect of Aspirin on Platelet Aggregation? A Randomized Crossover StudyAdamopoulos, Adam B MD*; Sakizlis, George N MD*; Nasothimiou, Efthimia G MD*; Anastasopoulou, Ioanna†; Anastasakou, Eugenia‡; Kotsi, Paraskevi†; Karafoulidou, Anastasia†; Stergiou, George S MD*Author Information From the *3rd Department of Medicine, University of Athens, Sotiria Hospital, Athens, Greece; †2nd Regional Blood Transfusion Centre and Haemophilia Unit Care, Laiko Hospital, Athens, Greece; and ‡Laboratory of Immunology, Sotiria Hospital, Athens, Greece. Received for publication March 15, 2009; accepted May 14, 2009. This study was presented at the XXIst Congress of the International Society on Thrombosis and Haemostasis, 2007. The authors report no conflicts of interest. Reprints: Efthimia G. Nasothimiou, MD, Hypertension Center, Third University Department of Medicine, Sotiria Hospital, 152 Mesogion Avenue, Athens 11527, Greece (e-mail: [email protected]). Journal of Cardiovascular Pharmacology: August 2009 - Volume 54 - Issue 2 - p 163-168 doi: 10.1097/FJC.0b013e3181af6d9c Buy Metrics Abstract It is common practice to coadminister proton pump inhibitors with aspirin to diminish the risk of upper gastrointestinal bleeding. This is the first study that investigated the potential impact of a proton pump inhibitor on aspirin effects on platelet aggregation. Twenty-four hypertensive subjects eligible for treatment with low-dose enteric-coated aspirin (LDECA) for primary prevention of cardiovascular disease were randomized to receive 100 mg LDECA or 100 mg LDECA plus 30 mg lansoprazole for 4 weeks. Then, participants were crossed over to the alternative regimen for another 4 weeks. Salicylic, gastrin, and pepsinogen I blood level counting were used to ensure adherence to treatment. Platelet aggregation was evaluated by light transmittance aggregometry and PFA100. The LDECA administration reduced arachidonic acid (P < 0.001), collagen (P < 0.01), and epinephrine (P < 0.001) tests. These changes paralleled an increase in collagen/epinephrine duration (P < 0.001) but not in collagen/adenosine diphosphate duration and platelet count. No significant difference was found in any of these platelets' function tests with LDECA alone versus LDECA plus lansoprazole. A significant increase in salicylic levels was observed in patients on LDECA as well as in those on LDECA plus lansoprazole, whereas gastrin and pepsinogen I levels were increased only when lansoprazole was added. These data suggest that the concomitant use of the lansoprazole at 30-mg daily does not influence the long-term effect of LDECA on platelet aggregation. Furthermore, they might imply that an interaction of LDECA with other proton pump inhibitors on platelet aggregation is unlikely. © 2009 Lippincott Williams & Wilkins, Inc.