The available evidence , predominantly from secondary -prevention observational studies , supports that dosages greater than 75 to 81 mg/d do not enhance efficacy , whereas larger dosages are associated with an increased incidence of bleeding events , primarily related to gastrointestinal tract toxicity .
CONCLUSIONS Currently available clinical data do not support the routine , long-term use of aspirin dosages greater than 75 to 81 mg/d in the setting of cardiovascular disease prevention .
Higher dosages , which may be commonly prescribed , do not better prevent events but are associated with increased risks of gastrointestinal bleeding
CONTEXT More than 50 million US adults take aspirin regularly for long-term prevention of cardiovascular disease , typically either 81 mg/d or 325 mg/d .
Controversy remains regarding the most appropriate long-term daily dose .
OBJECTIVE To review the mechanism of action of aspirin and the clinical literature for relationships among  aspirin dosage , efficacy , and safety .
EVIDENCE SYNTHESIS Although pharmacodynamic data demonstrate that long-term aspirin dosages as low as 30 mg/d are adequate to fully inhibit platelet thromboxane production , dosages as high as 1300 mg/d are approved for use .
Comparison of effects of high-dose and low-dose aspirin on restenosis after femoropopliteal percutaneous transluminal angioplasty.
BACKGROUND Long-term treatment with aspirin is recommended in patients with large-vessel peripheral arterial disease since these patients have a high risk of death from cardiovascular causes . Recent studies have demonstrated the prophylactic effect of low-dose aspirin in reducing the risk of cardiovascular events . Since aspirin is also recommended for prevention of late recurrence after peripheral angioplasty , the present study was undertaken to compare the effects of high-dose ( 1000 mg/d ) and low-dose ( 100 mg/d ) aspirin on long-term patency after femoropopliteal angioplasty . METHODS AND RESULTS Two hundred sixteen patients treated successfully by percutaneous transluminal angioplasty for femoropopliteal lesions were r and omly allocated to therapy with either 1000 or 100 mg aspirin daily . The follow-up was 24 months . The long-term results were analyzed using the Kaplan-Meier method , and differences between curves of cumulative patency were determined with the Wilcoxon and log-rank statistics . Complete follow-up information ( patency after 24 months , restenosis , and death ) was obtained in 207 patients . During the 2-year follow-up period , 72 patients --36 in the high-dose and 36 in the low-dose aspirin group , respectively -- developed angiographically verified reobstruction within the recanalized segment . By intention-to-treat analysis , the cumulative patency rates at 24 months were 62.5 % in the high-dose and 62.6 % in the low-dose aspirin group ( Wilcoxon , P = .97 ; log-rank , P = .97 ) . The cumulative survival at 24 months of follow-up was 86.6 % in the high-dose and 87.7 % in the low-dose aspirin group . The number of patients discontinuing therapy was 30 in the high-dose and 11 in the low-dose aspirin group ( P < .01 ) . Fewer patients receiving 100 mg of aspirin discontinued therapy because of gastrointestinal symptoms ( 4 versus 20 ) . CONCLUSIONS The data indicate that 100 mg aspirin is no less effective in the prevention of restenosis after femoropopliteal PTA than a 1000-mg dose and has fewer side effects
The available evidence , predominantly from secondary -prevention observational studies , supports that dosages greater than 75 to 81 mg/d do not enhance efficacy , whereas larger dosages are associated with an increased incidence of bleeding events , primarily related to gastrointestinal tract toxicity .
CONCLUSIONS Currently available clinical data do not support the routine , long-term use of aspirin dosages greater than 75 to 81 mg/d in the setting of cardiovascular disease prevention .
Higher dosages , which may be commonly prescribed , do not better prevent events but are associated with increased risks of gastrointestinal bleeding
CONTEXT More than 50 million US adults take aspirin regularly for long-term prevention of cardiovascular disease , typically either 81 mg/d or 325 mg/d .
Controversy remains regarding the most appropriate long-term daily dose .
OBJECTIVE To review the mechanism of action of aspirin and the clinical literature for relationships among  aspirin dosage , efficacy , and safety .
EVIDENCE SYNTHESIS Although pharmacodynamic data demonstrate that long-term aspirin dosages as low as 30 mg/d are adequate to fully inhibit platelet thromboxane production , dosages as high as 1300 mg/d are approved for use .