Does acetylsalicylic acid at varying doses and formulations affect platelet function and bleeding times in healthy subjects?
Daily doses of about 100 mg of acetylsalicylic acid achieve maximum inhibition of platelet function and increase in bleeding time, with no further changes at higher doses.
In an attempt to find the most appropriate dose and formulation(s) of acetylsalicylic acid (ASA) for thrombosis prophylaxis, healthy volunteers were given doses of ASA for 1 wk daily ranging from 50 to 3900 mg as either Aspro-Clear (soluble), Astrix (enteric coated pellets) or Ecotrin (enteric coated tablets). Platelet function and bleeding times were monitored. All doses of ASA significantly inhibited platelet function (p less than 0.05) and increased bleeding times (p less than 0.05) relative to control values. Irrespective of the formulation, maximum increases in bleeding time and platelet dysfunction were obtained with daily doses of about 100 mg, and no further changes were observed with higher doses.
McLeod et al. (Tue,) studied this question.