What are the options for postoperative analgesia?

Butorphanol 0.2-0.4 mg/kg IM can be given when sevoflurane is suspended, as long as at least 1 hour has elapsed since the previous dose and the animal's temperature is above 36.7°C (98°F).
Buprenorphine: 0.005 to 0.02 mg/kg SC, IM (dogs) and 0.005 to 0.01 mg/kg SC, IM, transmucosal (cats), can be substituted for butorphanol for postoperative pain treatment. This drug has a longer duration of effect (up to 6 to 8 hours), but may take up to 1 hour to reach peak effect. In cats, this agent can be administered transmucosally, NOT orally.
Hydromorphone: 0.05 to 0.2 mg/kg IM, SC, IV every 4 to 6 hours (dogs) and 0.05 to 0.1 mg/kg IM, SC, IV every 4 to 6 hours (cats). Make sure to closely monitor body temperature in cats, as hydromorphone can cause significant hyperthermia in felines. If a cat's temperature rises to >39.4°C (103°F), administration of buprenorphine at 0.005 to 0.01 mg/kg IV generally reverses most of the hyperthermic effect, while maintaining the analgesic effect.
Fentanyl in IIC, as described on page 21.
AINE can be administered when sevoflurane is suspended, as long as there are no contraindications for its use (renal insufficiency, liver disease, significant gastrointestinal compromise, or recent administration of corticosteroids) and the pet is well hydrated (has received intraoperative hydration) and does not present a significant risk of bleeding.