Pharmacokinetic Basis for Dosage Recommendations of Buprenorphine in Red-Eared Sliders (Trachemys scripta elegans)
Department of Environmental and Population Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, USA
Buprenorphine is a synthetic, mixed agonist-antagonist, opiate analgesic. Dosage recommendations for reptiles vary from 0.005–1 mg/kg.1 However, anecdotal observations are often the basis for the dosage used.2 In the current study, we did not perform a pain assessment study to evaluate the analgesic effect of buprenorphine in turtles but relied on the assumption that plasma levels of 1 ng/ml are analgesic, as has been reported for human surgery patients.5 We base this assumption on the fact that the opioid receptor genes are known to be highly conserved across multiple vertebrate orders.3,4
Fourteen red-eared sliders (Trachemys scripta elegans) were administered a single dose of 0.02 mg/kg of buprenorphine subcutaneously in the axillary area. Serial blood samples were collected immediately prior to administration and at 0.5, 1, 2, 4, 8, 12, 24, 48, and 72 hours after injection. The plasma level of buprenorphine was determined by radio-immunoassay (RIA) and standard pharmacokinetic values were calculated.
Our results suggest that in red-eared sliders (Trachemys scripta elegans), a dosage of 0.02 mg/kg buprenorphine subcutaneously results in a buprenorphine plasma level greater than 1 ng/ml for 18 hours.
1. Carpenter, J.W. 2005. Exotic Animal Formulary, 3rd ed. Elsevier Saunders, St. Louis, Missouri. P. 73.
2. Klaphake, E., C. Greenacre, J. Paul-Murphy, K. Sladky, and T. Storms. 2005. Roundtable: Reptile and Amphibian Analgesia. J. Herpetol. Med. Surg. 15:24–30.
3. Lorez, H.P., and M. Kemali. 1981. Substance P, met-enkephalin- and somatostatin-like immunoreactivity distribution in the frog spinal cord. Neurosci. Let. 26:119–124.
4. Stevens, C.W. 1988. Opioid antinociception in amphibians. Brain Res. Bull. 21:959–962.
5. Watson, P.J.Q., H.J. McQuay, R.E.S. Bullingham, M.C. Allen, and R.A. Moore. 1982. Single-dose comparison of buprenorphine 0.3 and 0.6 mg i.v. given after operation: clinical effects and plasma concentrations. Br. J. Anaesth. 54:37–43.