Effects of ticlopidine on platelet function and blood coagulation.

A double blind study was performed on 20 atherosclerotic patients. A placebo was administered to one group of 10 patients (group A) and ticlopidine (500 mg/day) was administered to another group of 10 patients (group B) for one month. ADP and collagen-induced platelet aggregation (PA), platelet malondialdehyde (MDA) produced by thrombin stimulation and plasma beta-thromboglobulin (beta TG) levels, prothrombin time, activated partial thromboplastin time (APTT) fibrinogen, antithrombin (AT) III fibrin(ogen) degradation products, alpha 2-antiplasmin and plasminogen were evaluated in both groups before and after treatment. No changes in PA, MDA and beta TG were seen in group A. Group B showed a significant decrease of PA, beta TG and a significant increase of MDA. No changes on blood coagulation data were seen in either group. This study suggests that ticlopidine is able to inhibit platelet function in vivo.