ABSTRACT
OBJECTIVES: The purpose of this study was to assess gastrointestinal blood loss with low dose (325 mg) plain and enteric-coated aspirin. METHODS: A total of 47 healthy volunteers participated in randomized, controlled acute and chronic trials. Seventeen participated in a repeated measures acute trial, and 30 participated in an independent sample chronic trial. Gastrointestinal blood loss was determined by obtaining 72-hour stool collections and quantitating Chromium-51 labeled erythrocytes. RESULTS: Acute phase trials: gastrointestinal blood loss during base line was 0.47 (+/- 0.11) mL/day, 0.96 (+/- 0.12) mL/day with enteric-coated aspirin (p < 0.0006), and 1.82 (+/- 0.35) mL/day with plain aspirin (p < 0.0001 vs. base line, p = 0.0476 vs. enteric-coated aspirin). Chronic phase trials: gastrointestinal blood loss was 1.12 (+/- 0.31) mL/day with enteric-coated aspirin (p = 0.0024 vs. control) and 2.60 (+/- 0.68) with plain aspirin (p < 0.0001 vs. control, p = 0.0364 vs. enteric-coated aspirin). CONCLUSIONS: During acute and chronic ingestion, plain aspirin at a dose of 325 mg/day significantly increased gastrointestinal blood loss when compared to control or enteric-coated aspirin values, although enteric-coated aspirin values were also significantly increased compared to control. Gastric adaptation does not decrease blood loss with low dose aspirin consumption.