A comparative study on the effect of dilazep and dipyridamole on some platelet functions.

It was the purpose of this study to examine the effect of 1,4-bis[3-(3,4,5-trimethoxybenzoyl-oxy)propyl]-perhydro-1,4-diazepine (dilazep) on platelet function in vivo, compared with that of dipyridamole. 15 patients were given oral doses of 300 mg dilazep daily, and another 15 patients received oral doses of 450 mg dipyridamole daily. Blood was withdrawn 2 and 4 weeks after the start of treatment, in each case 2 h after administration of the drug. The results were as follows: bleeding time was prolonged in both groups; there was a percentage reduction of circulating platelet aggregates in both groups, but this was statistically significant in the dilazep group only; platelet aggregation was decreased in both groups, several parameters (minimum dose required to induce aggregation, collagen lag phase) were statistically significantly improved in the dilazep group only; platelet malondialdehyde production was unchanged; no changes were demonstrated in platelet shape, fibrinogen concentration, partial thromboplastin time, or prothrombin activity.