The most appropriate postendoscopic management is to resume aspirin before discharge. This patient has upper gastrointestinal bleeding due to a low-risk (clean-based) ulcer. Aspirin should be resumed within 3 to 5 days for patients such as this with established cardiovascular disease. Aspirin reduces all-cause mortality (attributable primarily to cardiovascular, cerebrovascular, or gastrointestinal complications) tenfold over 30 days while increasing rebleeding rates only twofold. Long-term, daily proton pump inhibitor therapy should be offered to aspirin users who are Helicobacter pylori negative or those who use concomitant NSAIDs, anticoagulants, glucocorticoids, or other antiplatelet drugs.

This patient has no indication for changing his antiplatelet therapy from aspirin to clopidogrel. Although the relative risk for gastrointestinal bleeding is slightly lower with clopidogrel than aspirin, the absolute risk reduction from making the change is low enough that this patient's medication should not be switched; he has a low-risk ulcer and no other cardiovascular indication for clopidogrel (such as a recent drug-eluting stent). In addition, clopidogrel carries a high risk of bothersome side effects such as rash and diarrhea. It is also more expensive than aspirin.