How long may a methadone CRI be expected to last? We don't personally use methadone CRI but often we receive a referral that has been on methadone CRI.
Methadone CRIs were examined in an RSPCA clinic and reported in an abstract at BSAVA Congress in 2017. They showed that in dogs and cats the infusion at 0.1mg/kg/hr was effective, but that cats experienced more dysphoria than dogs. If the pain scores are low then you could observe these dogs and administer the next methadone when pain score increases - I would be thinking about 2hrs after stopping the infusion but that's just my experience as there are no studies looking at this specifically.