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

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.