High-dose buprenorphine results in a greater occurrence of postoperative hyperthermia than morphine in a randomized clinical trial in cats undergoing ovariohysterectomy.

OBJECTIVE: To compare the thermoregulatory and analgesic effects of high-dose buprenorphine versus morphine in cats undergoing ovariohysterectomy. ANIMALS: 94 client-owned cats. PROCEDURES: Cats were randomized to receive either buprenorphine 0.24 mg/kg or morphine 0.1 mg/kg subcutaneously (SC) during recovery from ovariohysterectomy. Body temperature measurements were obtained before anesthesia, during anesthesia (averaged), at extubation, and 2, 4, and 16 to 20 hours postoperatively. Signs of pain were assessed, and demographic characteristics were compared between groups. The effects of treatment and time on body temperature, point prevalence of hyperthermia (> 39.2 °C), and pain scores were compared with linear or generalized mixed-effect models. RESULTS: Cats receiving morphine (vs. buprenorphine) were older and heavier (both, P ≤ 0.005). Other group characteristics did not differ between treatments. Cats receiving buprenorphine (vs. morphine) had higher postoperative temperatures (P = 0.03). At 2, 4, and 16 to 20 hours after extubation, the point prevalence of hyperthermia was greater (P = 0.001) for cats receiving buprenorphine (55% [26/47], 44% [21/47], and 62% [27/43], respectively) versus morphine (28% [13/46], 13% [6/46], and 47% [21/44], respectively). There were no differences in pain scores between groups or over time. Five cats receiving buprenorphine and 6 receiving morphine required rescue analgesia within the 24-hour period. CLINICAL RELEVANCE: Administration of buprenorphine (0.24 mg/kg SC), compared with morphine (0.1 mg/kg SC), resulted in higher body temperatures without an apparent advantage with regard to analgesia during the first 20 postoperative hours than morphine. Opioid-induced postoperative hyperthermia could confound the diagnosis of fever from different sources.

Evaluation of oral maropitant as an antiemetic in cats receiving morphine and dexmedetomidine.

Objectives The aim of the study was to evaluate the antiemetic effects of maropitant, after oral administration, in cats receiving morphine and dexmedetomidine. Methods This prospective, blinded, randomized controlled trial involved 98 healthy female domestic shorthair cats. Cats were randomly assigned to receive maropitant PO 8 mg total (group M) administered 18 h prior to sedation with intramuscular dexmedetomidine 20 µg/kg and morphine 0.1 mg/kg, or no antiemetic treatment (group C). The occurrence of signs of nausea (sialorrhea and lip-licking), retching and emesis during the 30 mins following administration of dexmedetomidine and morphine was measured for each group. Results Two cats were excluded from the investigation. Cats in group M (n = 46) received an average of 2.5 mg/kg of maropitant PO. Compared with group C (n = 50), cats in group M had lower incidences of emesis (M: 4% vs C: 40%), retching (M: 8% vs C: 40%) and lip-licking (M: 30% vs C: 52%) (all P <0.05). The incidence of sialorrhea was not different between groups (M: 21% vs C: 22%). Conclusions and relevance Maropitant 8 mg total PO was effective in reducing morphine and dexmedetomidine-induced emesis by 10-fold, when administered as early as 18 h in advance to healthy cats. Maropitant PO could be useful for administration the evening prior to a scheduled procedure requiring sedation/anesthesia to decrease the incidence of emesis.