Effect of morphine, methadone, hydromorphone or oxymorphone on the thermal threshold, following intravenous or buccal administration to cats

At the doses used in this study, IV administration of methadone and hydromorphone, and buccal administration of methadone resulted in transient thermal antinociception. The results of this study do not allow us to predict the usefulness of these drugs for providing analgesia in clinical patients.