For veterinary professionals
October 2026
A guinea pig and a rabbit can weigh about the same, sit on the same surgery list and need very different pain plans. It's one of the things we encounter in practice that trips up experienced clinicians.
The principle doesn't change. Uncontrolled pain drives sympathetic activation, ileus, hyporexia and slower healing, and it sets the stage for central sensitization. Every surgical patient deserves multimodal analgesia: at least two drug classes acting on different pathways, so each can be used at a lower dose. What changes is the detail. Here are the differences I lean on most, as options to consider.
Rabbits. Buprenorphine is the workhorse, typically 0.03 to 0.05 mg/kg IV or IM. Bioavailability is poor by the subcutaneous and transmucosal routes, so I avoid them. Expect some ileus with any opioid, and don't count on cisapride to reverse it. Pushing to feline doses of high-concentration buprenorphine noticeably reduced food and water intake in rabbits, so I don't recommend it.
Guinea pigs and chinchillas. These rodents need considerably more: buprenorphine around 0.2 mg/kg SC, repeated roughly every 6 hours. Transmucosal buprenorphine can work in guinea pigs if it's repeated about every 4 hours. Extended-release buprenorphine has provided good analgesia in guinea pigs but was associated with weight loss, and it should be given well ahead of surgery. Guinea pig hydromorphone is 0.3 mg/kg, about every 2 to 3 hours IV or 4 to 5 hours IM. In chinchillas, hydromorphone at 2 mg/kg SC every 4 hours was needed to change limb-withdrawal responses, along with transient hyporexia and reduced fecal output, so plan nutritional support.
Ferrets. Buprenorphine at 0.04 mg/kg IM is a reasonable starting point, and hydromorphone at 0.2 mg/kg SC gives a short window of antinociception. Avoid morphine. It causes marked nausea and vomiting in ferrets.
Rats. Buprenorphine at 0.05 mg/kg is typical. Pica is common with buprenorphine in rats, so I remove bedding and anything else ingestible during recovery and offer favorite foods.
I generally start NSAIDs post-operatively, once temperature and blood pressure are stable, because anesthetic hypotension adds renal risk. There's no CKD staging system for these species, so cat guidelines are a cautious starting point rather than a rulebook.
In rabbits, meloxicam at 1 mg/kg every 24 hours has been shown safe for up to 29 days, and I occasionally use it every 12 hours based on the pharmacokinetic data. Higher doses have been associated with renal and hepatic changes, so I don't push past that. Ferrets do well at 0.2 mg/kg, and I've seen acute kidney injury in ferrets given more. For guinea pigs, pharmacokinetics support 1.5 mg/kg PO every 12 hours, though clinical efficacy and repeated-dose safety haven't been reported, so monitor bloodwork. Chinchillas have no published NSAID studies at all, and anything we do there is extrapolation. Rats are usually dosed at 1 to 2 mg/kg, but many older rats have subclinical chronic progressive nephropathy, so check bloodwork and a urinalysis, especially before repeated dosing.
I consider ketamine as a premedication or co-induction agent in most exotic companion mammal cases. It helps limit wind-up and lowers the induction dose. One firm rule: don't give ketamine intranasally to rabbits. Fatal epistaxis has been reported.
Alpha-2 agonists deserve caution. Medetomidine-vatinoxan meaningfully lowered blood pressure in rabbits, and many alpha-2 doses in circulation come from laboratory animal work and exceed what ECM practices commonly use. If you're unsure, talk to a species specialist or an anesthesiologist first.
Dental blocks (infraorbital/maxillary, mental/mandibular, palatine), great auricular and auriculotemporal blocks for ear surgery, and peribulbar blocks all reduce inhalant needs. Nerve locators and ultrasound guidance improve accuracy. In a 1 kg patient, calculate local anesthetic totals carefully, aspirate and inject slowly. Bupivacaine is particularly cardiotoxic, and lipid emulsion should be on hand.
Lidocaine and ketamine CRIs are worth adding for major surgery. In rabbits, a lidocaine CRI after a 2 mg/kg load reduces isoflurane MAC in a dose-dependent way. Published exotic mammal ranges run about 50 to 100 µg/kg/min for lidocaine and 0.3 to 1.2 mg/kg/h for ketamine intraoperatively, stepping down after surgery. Titrate both to effect.
Dose by species, not by size. Start NSAIDs once the patient is warm and normotensive, add a block or CRI whenever you can, and measure success by the return of normal behavior.
If you have questions about how to run a lidocaine-ketamine CRI, dosing buprenorphine in a guinea pig or choosing an NSAID for a ferret, reach out to Nashville's exotic companion mammal specialist. Dr. Logan Kopp, DABVP (Exotic Companion Mammal Practice) and Fellow in Companion Animal Pain Management, takes colleague consults and referrals at Priest Lake Veterinary Hospital, (615) 361-4646. Referral details are on the referring veterinarians page.
This content is for educational purposes for veterinary professionals. It doesn't establish a VCPR or replace clinical judgment for an individual patient. Drug use and doses should be checked against current references and adjusted for each case.