Clinical efficacy of hydrocodone-acetaminophen and tramadol for control of postoperative pain in dogs following tibial plateau leveling osteotomy.

OBJECTIVE: To evaluate clinical efficacy of hydrocodone-acetaminophen and tramadol for treatment of postoperative pain in dogs undergoing tibial plateau leveling osteotomy (TPLO). ANIMALS 50 client-owned dogs.

PROCEDURES: Standardized anesthetic and surgical protocols were followed. Each patient was randomly assigned to receive either tramadol hydrochloride (5 to 7 mg/kg, PO, q 8 h; tramadol group) or hydrocodone bitartrate-acetaminophen (0.5 to 0.6 mg of hydrocodone/kg, PO, q 8 h; hydrocodone group) for analgesia after surgery. The modified Glasgow composite measure pain scale was used to assess signs of postoperative pain at predetermined intervals by an investigator who was blinded to treatment group. Scoring commenced with the second dose of the assigned study analgesic. Pain scores and rates of treatment failure (ie, dogs requiring rescue analgesia according to a predetermined protocol) were compared statistically between groups.

RESULTS: 12 of 42 (29%; 5/19 in the hydrocodone-acetaminophen group and 7/23 in the tramadol group) dogs required rescue analgesic treatment on the basis of pain scores. Median pain score for the hydrocodone group was significantly lower than that of the tramadol group 2 hours after the second dose of study analgesic. The 2 groups had similar pain scores at all other time points.

CONCLUSIONS AND CLINICAL RELEVANCE: Overall, differences in pain scores between dogs that received hydrocodone-acetaminophen or tramadol were minor. The percentage of dogs with treatment failure in both groups was considered unacceptable.