The effectiveness of low dose slow release aspirin as an antiplatelet agent.

An open, randomized, parallel group study of three different aspirin preparations was carried out. The objective of this study was to compare their ability to inhibit the production of thromboxane A2 (measured as thromboxane B2 [TXB2]) from platelets. Three aspirin preparations were studied: Acetard 300 mg, Acetard 100 mg and Platet 100 mg. The study was conducted in 45 healthy adult volunteers and treatment continued once daily for 7 days. The results of the TXB2 assay show that the administration of all three treatment preparations produced a rapid drop in TXB2 levels of all volunteers. The baseline TXB2 level was reduced by 95% for all groups by day 3. Analysis by day showed a significant difference (P < 0.05) between treatments at day 1, with Acetard 100 mg having higher TXB2 levels than the other two groups. Analysis of changes from baseline showed a significant reduction (P < 0.05) in TXB2 levels at Days 1 to 14 for all three groups. Platelet aggregation also showed a significant reduction, being reduced to 10% of control at 7 days. It then reverted back to baseline by 28 days for all treatment groups. In conclusion, low dose aspirin is very effective as an antiplatelet agent and in a slow release form loses none of its patency.