Acetaminophen absorption and metabolism in celiac disease and Crohn's disease.

To investigate further the conflicting results in reports of drug absorption in patients with small intestinal mucosal disease, gastric emptying and the disposition of acetaminophen were assessed simultaneously in 41 subjects (13 controls, 12 patients with Crohn's disease, and 16 with celiac disease). Acetaminophen absorption as judged by plasma concentrations and gastric emptying were slower in patients with celiac disease and Crohn's disease. Total drug absorption as indicated by urinary recovery did not differ, but plasma acetaminophen half-life was shorter and glucuronide conjugation was enhanced in the patients with Crohn's disease. Contrary to expectation, the mean rate constant for acetaminophen absorption from the small intestine was not decreased in Crohn's disease and celiac disease. The abnormally slow acetaminophen absorption in the patients with Crohn's or celiac disease could be explained by slower gastric emptying of the drug solution.