Effect of intravenous diazepam on human lower oesophageal sphincter pressure under controlled double blind crossover conditions.

The effect of diazepam on the lower oesophageal sphincter (LOS) pressure is controversial. Therefore, a double-blind crossover study was performed on 18 healthy volunteers to determine the sphincter response to intravenous diazepam--70, 140, 280 microgram/kg, which correspond to a total dose of 5, 10, and 20 mg. respectively. After the 5 and 10 mg dose no signficant effect on LOS pressure could be observed when compared with placebo. After the 20 mg dose a significant rise in pressures (deltaPLOS) was recorded for 40 minutes with a maximum deltaPLOS of + 16.2 +/- 6.6 (mean +/- SEM) mmHg after 50 minutes (P less than 0.01) (46 +/- 1.3% increase above the basal pressure). It is concluded that diazepam does not affect lower oesophageal sphincter competence and therefore does not increase the risk of regurgitation and pulmonary aspiration in premedicated patients.