Inhaled fentanyl as a method of analgesia

TLDR

The study investigated aerosolized fentanyl for postoperative analgesia. The trial randomized 20 patients to placebo, 6 to 100 µg, and 7 to 300 µg inhaled fentanyl. Inhaled fentanyl at 300 µg significantly reduced postoperative pain, prolonged time to rescue analgesia, achieved low serum concentrations, and produced no respiratory or other adverse effects.

Abstract

Summary A study was undertaken to investigate the use of fentanyl by aerosol for postoperative analgesia. Seven patients had placebo, six received fentanyl 100 μg and seven were given fentanyl 300 μg. A significant improvement in postoperative pain, as assessed by linear visual analogue scale, was achieved in the higher dose group, and in both fentanyl groups the time to alternative analgesia was significantly longer than in the control group. Serum fentanyl levels after inhalation of 100 μg reached a plateau around 0.04 ng/ml and after 300 μg at around 0.1 ng/ml after 15 minutes. Inhaled fentanyl may have a useful analgesic effect despite these low serum levels; this supports the hypothesis that the mode of analgesia from inhaled opioids may be different from that after other routes of administration. There were no adverse effects such as respiratory depression, bronchospasm, nausea or drowsiness.