Ability of naloxone to enhance the colonoscopic appearance of normal colonvasculature and colon vascular ectasias

Background: Colon vascular ectasias are a common cause of lower intestinal bleeding among the elderly. The lesions may be difficult to diagnose at col onoscopy because they are small and their appearance may be influenced by t he patient's blood pressure, blood volume, and narcotic sedation during the procedure. The purpose of this study was to determine whether naloxone inf luenced the appearance of colon vascular ectasias at colonoscopy. Methods: One hundred forty-four patients older than 60 years undergoing com plete colonoscopy participated in the study. Medications were given in the usual doses. After a 2-minute inspection of the cecum and ascending colon, naloxone was given, followed by another 2-minute observation period. Photog raphic documentation of areas of interest was obtained before and after adm inistration of naloxone. Results: One hundred fourteen patients (79%) had no ectasias before or afte r administration of naloxone. Fourteen (9.7%) initially had normal vessels, and the vessels became more prominent; 4 (2.7%) initially had no ectasias, but ectasias later developed. Four patients (2.7%) had ectasias before adm inistration of naloxone that did not change; 8 (5.4%) had ectasias before a dministration of naloxone that increased in size (3 patients), number (7 pa tients), or both (2 patients). Conclusions: Naloxone can enhance the appearance of normal colonic vasculat ure and ectasias. Naloxone is an important adjunctive medication for patien ts undergoing examinations for lower intestinal bleeding.