Buprenorphine for cats: how it's given, side effects and safety

What is buprenorphine for cats used for?

Buprenorphine for cats is an opioid, a strong type of pain reliever. It’s one of the most widely used pain medicines in cats. A review of the research describes it as giving moderate pain relief that lasts a long time, with few side effects.

Vets use it for:

• Pain after surgery, such as spays, neuters and removing lumps
• Dental work, especially after tooth extractions
• Injuries, such as wounds, bite abscesses or falls
• Before anesthesia, as part of the sedation plan in the clinic

The 2022 ISFM acute pain guidelines note that buprenorphine combined with an NSAID gives adequate pain relief for dental and neutering procedures. On its own, it isn’t enough after major bone and joint surgery. Vets often pair it with an anti-inflammatory such as meloxicam, local anesthetic or other medicines. That “multimodal” approach tends to give the best pain relief in cats.

How is buprenorphine given to cats?

Your vet will set the dose for your cat and tell you how often to give it. In the clinic, buprenorphine is often injected. At home, it’s usually a liquid given by mouth in a special way, called oral transmucosal or buccal use.

1. Draw up exactly the amount your vet prescribed. It’s a potent drug, so measure carefully.
2. Hold your cat’s head gently and slip the syringe tip into the cheek pouch, at the side of the mouth. Under the tongue also works.
3. Squirt the liquid slowly into the pouch.

The medicine is absorbed through the gums, not the stomach. VCA notes that if your cat swallows it too quickly, it may work less well. Because it’s only a small amount of liquid, many cats accept it more easily than pills. Researchers describe it as a stress-free, “hands-off” way to give pain relief.

VCA says it usually takes effect in about 1 to 2 hours. If you miss a dose, give it when you remember, then wait the recommended time before the next one. Never give two doses at once.

Is there a long-acting buprenorphine for cats?

Yes, but these products are given in the clinic, not sent home.

The Simbadol label states it shouldn’t be dispensed for owners to give at home. The FDA says the same for Zorbium, and it carries a boxed warning about human abuse and exposure. If your cat had one of these at surgery, you may not need to give pain medicine at home at all, or only other medicines. Ask your vet before you leave.

The standard buprenorphine formulation is licensed for cats in the UK, Canada, Australia and other countries. In the US, VCA notes its use in cats is sometimes “off-label”, which is common and legal in veterinary medicine.

What are the side effects of buprenorphine for cats?

Most buprenorphine side effects in cats are mild and expected. Some look odd but are normal.

The review of buprenorphine studies says dilated pupils usually occur. It also says vomiting, nausea, unease and a high temperature are rare with standard buprenorphine. Mild temperature rises have been recorded, but didn’t seem to matter clinically. The labels for the long-acting products list a raised temperature as a common reaction, along with dilated pupils and hyperactivity. VCA lists seriously slowed breathing as uncommon but serious.

Effects can last longer in cats with liver or kidney disease. After a dose, keep your cat indoors in a quiet room with water and a litter box nearby.

Which cats need extra care with buprenorphine?

Tell your vet about every health problem and medicine before your cat starts buprenorphine. VCA advises it shouldn’t be used in cats allergic to opioids, or in pets treated with amitraz, an ingredient in some flea and tick products. It needs extra caution in cats with:

• Head injuries or other nervous system problems
• Liver, kidney, heart or lung disease
• An underactive thyroid or Addison’s disease
• Very young, very old or weak cats
• Pregnancy or nursing

Other calming or pain medicines can add to the sleepiness. These include benzodiazepines, tramadol and other sedatives. Gabapentin is often given alongside it, so ask your vet what to expect from the combination.

Why is buprenorphine a controlled drug?

Buprenorphine is also a human opioid. In the US, it’s a Schedule III controlled drug, and the Simbadol label warns it has abuse potential similar to other Schedule III opioids. It can cause dangerous, even fatal, slowed breathing in people who misuse it.

VCA explains that using a controlled drug in anyone other than the animal it was prescribed for is illegal. To keep your household safe:

• Store it in a locked cabinet or safe that can’t be easily carried off
• Limit access to the people who give the medicine
• Keep track of how much is left, so you’d notice if any went missing
• Keep it out of reach of children and other pets
• Store it at room temperature, away from light and heat
• Ask your vet how to dispose of any leftover medicine

How do I know if buprenorphine is working?

Don’t judge by the happy, rolling mood alone. The review notes that dilated pupils and behavior changes don’t match how well the pain is controlled. A cat can look blissed out and still hurt.

The 2022 guidelines list signs that suggest a cat is still in pain:

• Hunched posture, head held low, or lying very still
• Squinted eyes, flattened or rotated ears and a tense muzzle
• Hiding, not interested in you or their surroundings
• Growling, hissing or groaning, or reacting when the sore area is touched
• Licking or biting at the wound
• Not grooming, not eating, or chewing on one side after dental work

Check your cat when they’re awake, not while they’re sleeping, eating or grooming. The guidelines note that the Feline Grimace Scale, which scores ears, eyes, muzzle, whiskers and head position, can be used reliably by cat owners. Our is my cat in pain tool walks you through similar signs.

If your cat still shows several of these signs after a dose has had time to work, call your vet. Don’t give extra buprenorphine, and never give a human painkiller instead. Your vet can adjust the plan or add another medicine. For after-hours help, see our cat emergency guide, and for other medicines, browse our cat medications guides.

Written by the CatsMed Team from the sources above. Reviewed by Dr. Jarod Grantland, DVM. It isn’t a substitute for seeing a vet. See how we research.