Idiopathic slow-transit constipation: whole gut transit times, measured by a new simplified method, are not shortened by opioid antagonists.

A simplified method for measuring mean whole gut transit time has been validated which avoids stool collection and is suitable for out-patients. Radio-opaque markers are swallowed daily for 14 days and the mean whole gut transit time is derived directly from an abdominal X-ray. Using this new technique, neither nalmefene (in a double-blind study of six patients) nor naloxone (in an open study of four patients) shortened mean whole gut transit time in idiopathic slow-transit constipation.