Effects of midazolam on small bowel motility in humans

Benzodiazepines are used as sedatives for some intestinal procedures and as hypnotics, and this is the reason for studying their effects on duodenojejunal motility.

Antroduodenojejunal manometry was performed in 13 healthy volunteers on two different occasions, when placebo or midazolam were given intravenously (randomized, double-blind). A bolus dose of midazolam 0.03 mg/kg was followed by 0.015 mg/kg after 1.5, 3 and 4.5 h. After 5 h observation of interdigestive motility, the volunteers were given a test meal and recording continued for another hour. Twenty-eight motility variables were compared.

With midazolam the median motility index of phase III in the proximal duodenum was increased by 37% (P < 0.05), which was a consequence of both a longer duration (P < 0.01) and higher pressure amplitudes (P < 0.05), compared with placebo. A longer duration (9%) of phase III was also seen in the distal duodenum (P < 0.05). With midazolam the duration of the migrating motor complex was shortened by 27% (P < 0. 05). No statistically significant difference was found for the number of episodes of phase III registered (P=0.09), or for the other 22 motility variables compared including the duodenal retroperistalsis in late phase III.

Midazolam does affect some aspects of duodenal motility, especially in the proximal part, but phase III-related retroperistalsis is not affected.