Use of selective opiate receptor inhibitors to prevent postoperative ileus.

Ileus is a common postoperative complication after major abdominal surgery. Surgical manipulation of the bowel and stimulation of opiod receptor are the main causes of ileus. An investigational drug (ADL 8-2698, Alvinopam) a selective opioid antagonist with a very low oral absorption was recently introduced to clinical medicine. Unlike other opioid antagonist its activity is restricted to GI tract, it is potent, has a long duration of action, is orally effective, does not readily cross the blood-brain barrier even after intravenous administration in animals. Two randomized controlled clinical studies tested its effects in humans. Liu et al.'s study confirmed peripheral restriction of ADL 8-2698 by its lack of central effect on morphine analgesia and pupil miosis. They also showed that ADL 8-2698 prevents increases in gastrointestinal transit time. Taguchi et al. concluded that high dose (6 mg) of ADL 8-2698 archived fast recovery of gastrointestinal function, without antagonising analgesic efficacy of systemic opioid. In summary, selective inhibition of gastrointestinal opioid receptor by a peripherally restricted oral antagonist speeds recovery of bowel function, shortens times of hospitalization and preserves the analgesic effects of opiods.