Butorphanol decreases edema following carrageenan-induced paw inflammation in rats

The objectives of this study were to evaluate the anti-inflammatory effects and possible drug interactions of butorphanol by using carrageenan-induced paw inflammation in rats. We injected the right hind footpads of 64 female Sprague-Dawley rats (approximate weight, 100 g) with 50 microL of a 0.5% solution of carrageenan. Indomethacin (0, 1, 2.5, or 5 mg/kg) was administered by gavage to each of four groups 1 h prior to carrageenan injections. Half of the animals in each group received butorphanol (2 mg/kg) subcutaneously 1 h prior to carrageenan injections. Butorphanol decreased paw inflammation following carrageenan injections with or without concurrent administration of indomethacin. No drug interaction with indomethacin was observed. In conclusion, when using butorphanol for its analgesic properties, investigators should be mindful of the drug's anti-inflammatory effects, which may interfere with the experimentation.