Comparison of analgesic effects of khat (Catha edulis Forsk) extract, D-amphetamine and ibuprofen in mice

We have compared the analgesic properties of khat (Catha edulis Forsk) extr act, amphetamine and ibuprofen in mice. After intragastric administration o f the drugs analgesia was measured relative to water-injected controls usin g the hot-plate, the tail-flick, and abdominal-constriction tests. At the highest doses examined (amphetamine 1.8 mg kg(-1), ibuprofen 90 mg k g(-1), khat extract 1800 mg kg(-1)), all three substances produced analgesi a, but the order of efficacy varied with the test. Khat and ibuprofen were significantly different from the control in the hot-plate assay at three or more time points post-injection. In the tail-flick test, khat and amphetam ine were efficacious; ibuprofen means were somewhat lower but still signifi cantly different from control. Higher doses of the drugs decreased the numb er of responses in the acetic acid-induced abdominal-constriction assay. We conclude that khat, like amphetamine and ibuprofen, can relieve pain. Di fferences in assay results may reflect differences in modes and sites of ac tion, as well as in the type of pain generated by the chemical and thermal stimuli for nociception.