Analgesic effects of tramadol, tramadol-gabapentin, and buprenorphine in an incisional model of pain in rats (Rattus norvegicus)

J Am Assoc Lab Anim Sci. 2011 Mar;50(2):192-7.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amines / pharmacology*
  • Analgesics / pharmacology*
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Buprenorphine / pharmacology*
  • Cyclohexanecarboxylic Acids / pharmacology*
  • Gabapentin
  • Hyperalgesia
  • Male
  • Models, Animal
  • Pain, Postoperative / drug therapy
  • Pain, Postoperative / veterinary*
  • Postoperative Period
  • Rats*
  • Rats, Sprague-Dawley
  • Tramadol / pharmacology*
  • Weight-Bearing
  • gamma-Aminobutyric Acid / pharmacology*

Substances

  • Amines
  • Analgesics
  • Anti-Inflammatory Agents, Non-Steroidal
  • Cyclohexanecarboxylic Acids
  • Tramadol
  • Buprenorphine
  • gamma-Aminobutyric Acid
  • Gabapentin