A comparison of preoperative tramadol and morphine for the control of early postoperative pain in canine ovariohysterectomy.
OBJECTIVE
To compare morphine with tramadol for the management of early postoperative pain following ovariohysterectomy after pyometra in dogs.


METHODS
Prospective randomized blinded clinical trial.


METHODS
Thirty female dogs, 2-14 years old.


METHODS
Animals were randomly divided into two equal groups. Group 1 received 0.2 mg kg-1 of morphine IV and group 2 received 2 mg kg-1 of tramadol IV after the induction of anesthesia. The dogs were premedicated with acepromazine, and anesthesia was induced with intravenous midazolam and ketamine. Isoflurane was used for the maintenance of anesthesia. The variables measured were: analgesia; sedation; cardiac and respiratory rates; arterial blood pressure; end-tidal isoflurane and carbon dioxide (Pe'CO2); oxyhemoglobin saturation (SpO2); plasma catecholamines; serum cortisol and glucose concentrations; pH and blood gases. The animals were monitored for 6 hours after the administration of the analgesic agent.


RESULTS
There were no differences between the two groups with regard to analgesia, sedation, SpO2, pH and blood gases, cardiovascular variables, glucose, catecholamine and cortisol concentrations. Forty minutes postopioid administration, the end-tidal isoflurane concentration was significantly lower in the morphine-treated group as compared to the tramadol group. At 30 minutes following opioid injection, Pe'CO2 was significantly higher in the morphine group than in the tramadol group. Two dogs in the tramadol group and one in the morphine group were given morphine postoperatively because of increasing pain scores.


CONCLUSIONS
Morphine and tramadol, administered preemptively can be used safely in dogs to control early pain after ovariohysterectomy without significant adverse effects.
Mastrocinque
Sandra
S
Surgery Department, School of Veterinary Medicine and Zootechnic, University of São Paulo, São Paulo, Brazil.
Fantoni
Denise T
DT
D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D004285:Dogs / Q000502:physiology* / Q000601:surgery; D005260:Female; D007044:Hysterectomy / Q000662:veterinary; D007262:Infusions, Intravenous / Q000662:veterinary; D009020:Morphine / Q000008:administration & dosage*; D010052:Ovariectomy / Q000662:veterinary; D010147:Pain Measurement / Q000187:drug effects / Q000662:veterinary; D010149:Postoperative Pain / Q000517:prevention & control*; D011292:Premedication; D011446:Prospective Studies; D012119:Respiration / Q000187:drug effects; D016037:Single-Blind Method; D014147:Tramadol / Q000008:administration & dosage*
D000701:Analgesics, Opioid; D014147:Tramadol; D009020:Morphine