title: Analgesic effects of tramadol, tramadol-gabapentin, and buprenorphine in an incisional model of pain in rats (Rattus norvegicus).
abstract: Postoperative pain management in laboratory animals relies heavily on a limited number of drug classes, such as opioids and nonsteroidal antiinflammatory drugs. Here we evaluated the effects of saline, tramadol, tramadol with gabapentin, and buprenorphine (n = 6 per group) in a rat model of incisional pain by examining thermal hyperalgesia and weight-bearing daily for 6 d after surgery. All drugs were administered preemptively and continued for 2 consecutive days after surgery. Rats treated with saline or with tramadol only showed thermal hyperalgesia on days 1 through 4 and 1 through 3 after surgery, respectively. In contrast, buprenorphine-treated rats showed no thermal hyperalgesia on days 1 and 2 after surgery, and rats given tramadol with gabapentin showed reduced thermal hyperalgesia on days 2 and 4. For tests of weight-bearing, rats treated with saline or with tramadol only showed significantly less ipsilateral weight-bearing on day 1 after surgery, whereas rats given either buprenorphine or tramadol with gabapentin showed no significant change in ipsilateral weight-bearing after surgery. These data suggest that tramadol alone provides insufficient analgesia in this model of incisional pain; buprenorphine and, to a lesser extent, tramadol with gabapentin provide relief of thermal hyperalgesia and normalize weight-bearing.
authors: Department of Comparative Medicine, Stanford University School of Medicine, Stanford, California, USA. gpmckeon@stanford.edu
authors: Gabriel P
authors: GP
authors: McKeon
authors: Cholawat
authors: C
authors: Pacharinsak
authors: Charles T
authors: CT
authors: Long
authors: Antwain M
authors: AM
authors: Howard
authors: Katechan
authors: K
authors: Jampachaisri
authors: David C
authors: DC
authors: Yeomans
authors: Stephen A
authors: SA
authors: Felt
mesh_terms: D000588:Amines / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002047:Buprenorphine / Q000494:pharmacology*; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D000077206:Gabapentin; D006930:Hyperalgesia; D008297:Male; D023421:Models, Animal; D010149:Postoperative Pain / Q000188:drug therapy / Q000662:veterinary*; D011184:Postoperative Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D014147:Tramadol / Q000494:pharmacology*; D016474:Weight-Bearing; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D000588:Amines; D000700:Analgesics; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003509:Cyclohexanecarboxylic Acids; D014147:Tramadol; D002047:Buprenorphine; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin