title: Evaluation of the analgesic effects of oral and subcutaneous tramadol administration in red-eared slider turtles.
abstract: OBJECTIVE
  To determine the dose- and time-dependent changes in analgesia and respiration caused by tramadol administration in red-eared slider turtles (Trachemys scripta).
  
  
  METHODS
  Crossover study.
  
  
  METHODS
  30 adult male and female red-eared slider turtles.
  
  
  METHODS
  11 turtles received tramadol at various doses (1, 5, 10, or 25 mg/kg [0.45, 2.27, 4.54, or 11.36 mg/lb], PO; 10 or 25 mg/kg, SC) or a control treatment administered similarly. Degree of analgesia was assessed through measurement of hind limb thermal withdrawal latencies (TWDLs) at 0, 3, 6, 12, 24, 48, 72, and 96 hours after tramadol administration. Nineteen other freely swimming turtles received tramadol PO (5, 10, or 25 mg/kg), and ventilation (V(E)), breath frequency, tidal volume (V(T)), and expiratory breath duration were measured.
  
  
  RESULTS
  The highest tramadol doses (10 and 25 mg/kg, PO) yielded greater mean TWDLs 6 to 96 hours after administration than the control treatment did, whereas tramadol administered at 5 mg/kg, PO, yielded greater mean TWDLs at 12 and 24 hours. The lowest tramadol dose (1 mg/kg, PO) failed to result in analgesia. Tramadol administered SC resulted in lower TWDLs, slower onset, and shorter duration of action, compared with PO administration. Tramadol at 10 and 25 mg/kg, PO, reduced the V(E) at 12 hours by 51% and 67%, respectively, and at 24 through 72 hours by 55% to 62% and 61 % to 70%, respectively. However, tramadol at 5 mg/kg, PO, had no effect on the V(E).
  
  
  CONCLUSIONS
  Tramadol administered PO at 5 to 10 mg/kg provided thermal analgesia with less respiratory depression than that reported for morphine in red-eared slider turtles.
authors.affiliation: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: Bridget B
authors.initials: BB
authors.lastname: Baker
authors.forename: Kurt K
authors.initials: KK
authors.lastname: Sladky
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Johnson
mesh_terms: D000284:Administration, Oral; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000627:therapeutic use*; D000818:Animals; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D007279:Injections, Subcutaneous; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy*; D014147:Tramadol / Q000008:administration & dosage* / Q000627:therapeutic use*; D014426:Turtles
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol; D009020:Morphine