Effect of meptazinol on drug absorption and gastric emptying

The rate of paracetamol absorption after oral administration was used as an indirect estimate of the rate of gastric emptying in 24 patients before minor surgery. Patients who received 10 mg morphine or 100 mg meptazinol i.m. had significantly delayed absorption as shown by a lower peak concentration and a delayed time to peak. The mean AUC at 90 min was 1,590, 642 and 159 micrograms min ml-1 after saline, morphine and meptazinol respectively. Meptazinol delayed paracetamol absorption more than morphine.