Effect of nabumetone and aspirin on colonic mucosal bleeding time

Background: The management of patients taking aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) who require colonoscopy remains controversial because of concerns over bleeding after biopsy or polypectomy. Aim: To determine whether patients using the NSAID nabumetone, a non-acidic prodrug with mixed activity against cyclooxygenase-1 (COX-1) and COX-2, exhibited prolonged mucosal bleeding times and how this might compare with mucosal bleeding times in patients using aspirin. Methods: We assessed triplicate mucosal bleeding times in patients undergoing screening flexible sigmoidoscopy. We compared 90 patients who had taken no aspirin or NSAIDs within the previous 2 weeks, to 60 patients who had received nabumetone 1 g b.d. by mouth for the previous 2 weeks, and 30 patients who had taken 325 mg aspirin daily for the previous 2 weeks. In each case, the investigator performing the study was blinded to the patient's medication. Results: Mucosal bleeding times did not differ significantly among control or nabumetone-using patients. However, the patients receiving aspirin exhibited significant prolongation. Mucosal bleeding time correlated statistically significantly, but weakly, with skin bleeding time. Conclusions: Nabumetone does not appear to prolong mucosal bleeding time after mucosal pinch biopsy, and skin bleeding time does not reliably screen for prolonged mucosal bleeding time.