Acetyl salicylic acid resistance and inhibition to platelet aggregation
The adverse side-effects of Acetyl Salicylic Acid (ASA) are mainly gastrointestinal bleeding. The objective is to determine if 50 mg ASA is as effective as 100 mg when used in normal healthy subjects. The 18 normal subjects had a normal platelet count of mean 301 ± 72.3 x 109/L. Significant (P = <0.001) platelet inhibition was seen in 15 subjects ingesting 50 mg ASA (mean 50.3 ± 21.9%) and 100 mg ASA (mean 75.7 ± 19.3%). Further significantly enhanced (P = <0.001) inhibition was seen in 100 mg ASA compared to 50 mg. Three subjects were non-responders to 50 mg ASA (16.7%) and two to 100 mg (11.1%). The study showed that a 100 mg ASA dose is better suited for antiplatelet therapy compared with 50 mg. Significantly greater platelet inhibition was seen with 100 mg ASA with no gastrointestinal bleeding or other side-effects reported. ASA resistance was seen in 16.7% of subjects ingesting 50 mg ASA and 11.1% ingesting the 100 mg dose.