Inhaled nebulised fentanyl for postoperative analgesia

The effects of three concentrations of inhaled nebulised fentanyl citrate solution given for postoperative pain relief were studied. Each of 30 patients inhaled one dose of 3 ml of solution nebulised over 9 min. A combined analysis of pain relief, time to further analgesia and effect on respiratory frequency showed the highest concentration (318 micrograms/ml fentanyl base) to be more effective (p less than 0.01) than the two lower concentrations (159 micrograms/ml and 64 micrograms/ml) which were indistinguishable from each other. There were no major side effects. This study provides evidence for the efficacy and safety of inhaled fentanyl for postoperative analgesia. Estimation of the delivered doses did not support the hypothesis that fentanyl is more effective by this route compared with other parenteral routes. Further studies are required to improve the method of delivery and investigate the pharmacodynamic features of this technique.