[Midazolam plus ketamine as premedication for colonoscopies. A double-blind, randomized study].

In a prospective, double-blind, placebo-controlled, parallel-group, clinical study of 129 consecutive patients examined by one experienced endoscopist, we compared two premedication schedules: midazolam plus placebo and midazolam plus ketamine. 40% of the patients receiving midazolam alone needed a second injection, and 15% had to be excluded for failure. In the ketamine-group, 27% received a second injection; there were no treatment failures. The combination of both drugs proved to be safe without added risk. The combination provides more reliable sedation and analgesia and is judged as superior by the endoscopist, and patient's acceptance for re-endoscopy is higher.