Effect of low-dose aspirin treatment on human platelet aggregation

1. The effect of aspirin 50 mg/day during 28 days on human platelet aggregation (PAG) induced by ADP and collagen has been studied in 12 healthy volunteers. 2. The results show that aspirin treatment reduces both ADP and collagen-induced PAG (P less than 0.01). 3. Maximal inhibition of PAG appears in the second week of treatment for ADP-induced PAG (41.1%) and in the fourth week for collagen-induced PAG (50.2%). No significant differences exist between the controls taken along the treatment during the 28 days of the study. 4. The data suggest that the low-dose of aspirin tested provides adequate PAG inhibition to be used in the prophylaxis of thromboembolism patients, thus avoiding intolerances to higher dosages.