Absorption and efficacy of acetylsalicylic acid in patients with short bowel syndrome.

ABSTRACT

BACKGROUND: The patients with a short bowel (SB) frequently require antiplatelet therapy. Resection of the bowel is likely to modify the absorption and first-pass effect of drugs. No data on the absorption and efficacy of the cardiovascular dose of aspirin (75-160 mg) in these patients have been published. OBJECTIVE: To evaluate the efficacy of a low dose of aspirin in patients with SB caused by mesenteric ischemia. METHODS: The efficacy of a low dose of aspirin was assessed in 10 consecutive SB patients, both 1 hour and 24 hours after administration (peak and trough value, respectively). The primary criterion was the inhibition of platelet aggregation, as assessed by light transmission aggregometry, triggered with 0.5 mg/mL arachidonic acid. Biological efficacy of aspirin was also evaluated by serum thromboxane B2 value and by platelet function analyzer-100. RESULTS: At its peak value, aspirin had the expected efficacy, as demonstrated both by light transmission aggregometry and the other methods. However, 24 hours after administration, as many as 30% of patients had lost the pharmacological efficacy of their aspirin. CONCLUSION: We show for the first time that with at least 30 cm of small intestine, all patients with SB absorb sufficient oral aspirin in a cardiovascular dose to rapidly exert the expected level of antiplatelet activity. But given only once daily, aspirin does not provide stable 24-hour antiplatelet protection in 30% of patients, because of increased platelet turnover, as usually observed in patients with extensive vascular pathology, diabetes, or inflammation.