Effects of aspirin on platelet aggregation in smokers and nonsmokers

OBJECTIVE: TO assess the relative antiaggregatory ability of aspirin on platelets of smoking and nonsmoking healthy volunteers. DESIGN: Prospective, randomized, crossover study. SETTING: Tertiary-care teaching institution. SUBJECTS: Eighteen healthy smoking and nonsmoking male volunteers. INTERVENTIONS: Each subject received aspirin 325 mg or ticlopidine 250 mg bid as an active control for 7 days in a crossover manner separated by a 1-month washout period. Whole blood platelet aggregation was measured on four occasions, twice at baseline and once after each drug treatment. OUTCOME MEASUREMENT: Whole blood ex vivo platelet aggregation in terms of impedance (Omega) and adenosine triphosphate (ATP) release (nmol), as assessed using Lumi-aggregometry. RESULTS: Aspirin was associated with significantly less ATP release in both smokers (p = 0.01) and nonsmokers (p = 0.003). No significant differences in platelet aggregation were found between smokers and nonsmokers at baseline or with any treatment phases. Sixty-seven percent and 17% of volunteers receiving ticlopidine and aspirin, respectively, reported adverse effects. CONCLUSIONS: Twice-daily administration of aspirin for 7 days to healthy volunteers was well tolerated and also reduced platelet aggregation significantly regardless of smoking status.