Effects of Concurrent Calcium Channel Blocker on Antiplatelet Efficacy of Clopidogrel Therapy: A Systematic Review.

Clopidogrel is a widely used drug in clinical practice. Controversy persists as to whether it interacts with proton pump inhibitors. Recently, research interest has grown in the area concerning an interaction of clopidogrel with calcium channel blockers. Multiple studies have been conducted to evaluate the effect of calcium channel blockers on the efficacy of clopidogrel, both in vitro and in vivo. The authors aim to present a systematic review of the published studies in the literature. Various terms were searched in PubMed, Web of Science, and The Cochrane database. Abstracts of studies were read and based on strict exclusion criteria; a study was included/excluded into the review. A total of 424 studies were initially included. Based on exclusion criteria, 22 studies were finally included in the review. Various studies report widely different results regarding the effects of calcium channel blockers on antiplatelet efficacy of clopidogrel. Large prospective studies are needed to delineate the association or lack thereof.