Variability of the antithrombotic effect of acetylsalicylic acid with the administration of different dosages: reality or myth?

Abstract

Introduction and objectives: Acetylsalicylic acid (ASA) has both antithrombotic and anti-inflammatory effects, the latter being achieved when administered at higher doses (500 mg, 1000 mg per os). However, it is not known whether the anti-inflammatory effect decreases the antithrombotic potency of ASA. This experimental study intends to assess whether ASA maintains its antithrombotic effect when administered in an anti-inflammatory dose.

Methods: Twenty healthy volunteers were recruited and randomized into four groups. Each group ingested ASA 100 mg, 300 mg, 500 mg, and 1000 mg respectively. Their basal platelet function was measured using PFA-200 technology and reassessed one hour after ASA ingestion.

Results: The volunteers were all antiaggregated after ingestion of ASA, regardless of the dose taken. No statistical significance was found regarding age or gender. A subanalysis was performed, comparing the two groups that ingested lower dosages (100 mg and 300 mg) against the group that ingested higher dosages (500 mg and 1000 mg). The results were statistically significant, suggesting higher dosages may correspond to a higher antithrombotic effect.

Conclusions: Acetylsalicylic acid maintains its antithrombotic effect when administered in an anti-inflammatory dose. There is no clear association between the potency of antithrombotic effect and the ASA dose administered; however, our subanalysis suggests that higher dosages may correspond to a higher potency of antiaggregation.