The effects of premedication drugs on the lower oesophageal high pressure zone and reflux status of rhesus monkeys and man.

Thirty-five human volunteers and eight Rhesus monkeys were studied with standard gastrooesophageal manometric techniqes and their reflux status was evaluated witha pH probe placed in the lower oesophagus. morphine sulphate, pethidine hydrochloride, or idazepam was given intravenously until drowsiness was induced. The manometric and pH studies were repeated. All three drugs decreased the lower oesophageal high pressure zone and increased the probability of relux in both monkeys and man. Thes findings are relevant in the preparation of patients for surgery since gastrooesophageal reflux and pulmonary aspiration may be a problen in the pre-and postoperative phases.