[Interaction of morphine and non-steroid anti-inflammatory agents]

A study was made of the analgesic action of combined morphine and nonsteroidal anti-inflammatory agents (NAIA)--voltaren, ibuprophen and metindol. It was established that injection of morphine prior to NAIA gives rise to a reduction in the analgesic effect, whereas the combined use of the drugs or administration of NAIA following morphine entails the retention of the effect. Pretreatment with prostaglandin E produces opposite changes in the effect of the analgesics--potentiation of analgesia upon morphine injection and its reduction after NAIA. The data obtained present indirect evidence for the importance of prostaglandins in the antagonism of morphine and NAIA.