What Is Buprenorphine for Cats?

Daphne Mallory

Veterinarians will sometimes prescribe buprenorphine for cats that are suffering from pain. The drug is a powerful opiate and is available only by prescription. Its use is monitored by the U.S. Drug Enforcement agency because of its opiate properties. Although it is formulated for humans, vets are allowed to use buprenorphine for treating moderate pain in cats and some other animals. In these cases, it is prescribed as an off-label drug. Buprenorphine can cause some side effects in cats, but it is very uncommon for an overdose to happen.

Buprenorphine has a sedative effect on cats.
Buprenorphine has a sedative effect on cats.

Owing to the known potential for abuse of opiates, buprenorphine is often administered to the cat directly at the veterinary clinic. The U.S. Food and Drug Administration has not approved the drug for use in animals as of 2011, but vets commonly prescribe it to cats because of its effective pain-relief properties. Buprenorphine interacts with the central nervous system to alleviate pain. The relief can last up to eight hours or longer, and the sedative effect of the drug helps cats to rest so they can heal. Buprenorphine is sold in 1-mL ampoules, which the vet will administer in small doses into the cat’s mouth. The drug can quickly be absorbed by the cat’s gums, where it enters the bloodstream. It can also be injected into the cat’s veins or directly into a muscle that is affected by pain.

Buprenorphine is an opiate that is sometimes prescribed for cats in severe pain.
Buprenorphine is an opiate that is sometimes prescribed for cats in severe pain.

There are some common side effects of buprenorphine that veterinarians will warn cat owners about. The most common one is a feeling of sedation, which often happens with opiate drugs. It can also cause cats to breathe slowly. While cats can experience nausea, delirium, and strange behavior changes on other opiates, these reactions are usually not present when using buprenorphine. The drug is usually administered twice a day at 12-hour intervals, or more often in cats that are experiencing intense pain.

Veterinarians will not prescribe buprenorphine for cats that are suffering from certain conditions. Cats that are elderly, severely debilitated, or that have suffered a severe head trauma should not be given this drug. Vets will not prescribe it for cats that have kidney disease and certain other serious conditions and will use it only with extreme caution in cats that have liver disease. Cats that are taking antihistamines, tranquilizers, and other drugs can have adverse reactions to buprenorphine if it’s administered at the same time. Pet owners should inform their vet about any medications their cat is already taking prior to the use of the drug and should closely monitor their pet for adverse reactions while it’s being used.

Veterinarians will not prescribe buprenorphine for cats that are suffering from certain conditions.
Veterinarians will not prescribe buprenorphine for cats that are suffering from certain conditions.

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Discussion Comments


@Anon 989765: My cat is experiencing exactly that! His pupils are dilated and he seems to be hallucinating as he looks paranoid. He's looking at one spot for hours really worried, like there was something or someone there.

We came home from the vet Friday evening because he was in pain with bladder. Waiting for test results on Monday to come back and meantime they prescribed him Buprenorphine one syringe every 12 hours orally.

His kidneys may be suspect in his pain too and now i just read that this med is not suppose to be given to cats with kidney problems. I skipped the night dose as it is Sunday night now and the paranoia seem to be easing as the morning dose is wearing off, but tomorrow morning I'm calling the vet first thing!

I think there are more side effects than indicated and hallucinations/paranoia is one of them!


It does cause dilated eyes, so that is not a thing to worry about. My cat had stitches and they sent me home with syringes to be given orally every 8 hours, but he was so sleepy I just do it every 12 hours. Just keep an eye on them while they're taking the meds.


My 4-year-old cat just had three teeth extracted yesterday and the vet gave him a sustained-release injection of buprenorphine before sending him home with me. He was hyperactive for more than 24 hours after I got him home (and seemed almost paranoid at times, which made me wonder if he was hallucinating). I don't think he has slept at all (I was up with him most of the night) and has only seemed to start calming down in the last few hours (he's been home for about 30 hours now. He's still not sleeping, but at least he's lying still.

He has been extremely affectionate, has rolled and wriggled around on the floor like a female cat in heat, and has had a voracious appetite. And his pupils are still very dilated. He sits and gazes for long periods of time, as though he's in a trance.


My cat developed dilated pupils and was very sedated while on buprenorphine at home after a procedure. It wears off after six or eight hours.


My cat had four teeth extracted on Thursday. He came home that afternoon and stayed awake and active for about 30 hours.

We're about 48 hours in now and while he has slept now, he's still a different cat.

I'm really not happy about this. I don't think the vet emphasized the possible side effects nearly enough.

He went in a happy cat and came out changed and not in a good way. I think we will be looking for a new vet next year.


My male 11 year old cat had a dental cleaning and tooth extraction today. As soon as I got him home and out of his carrier he began his loopy exploration of the house, making sure his litter box, food and water were all where he remembered.

He was extremely high energy and was sort of galloping all over. His eyes dilated so that he looked like a cartoon cat! He was prescribed buprenorphine every 8 hours with a first dose at 8 p.m. tonight. The erratic behavior began anew with more energy than he's had in years. And an appetite that won't stop! He just keeps eating and roaming the house. Definitely not tired and I anticipate it will be a long night. Will call vet in AM to make sure dose is accurate. Crazy!


I'm not sure how old this post is, but my cat was also just prescribed buprenex in small syringes. They gave him a shot of it and told me to start giving him the oral meds three times a day, so I gave him one later that night only to see that within 30 minutes to 1 hour his eyes completely dilated, he stopped meowing (and he's usually a very vocal cat), and was acting a little loopy.

I called the vet this morning before giving him his morning dose and they said to only give him the meds two times a day now. I'm still unhappy with that response since he had a reaction only after the first dose!!


I accidentally gave my kitten buprenorphine as an injection in her scruff because I didn't understand the vet and they left the needles in. Apparently it was supposed to be oral. This article says the sometimes it is given as an injection, so will she be all right?


My cat is taking buprenorphine for cancer pain. It is expensive. Can one use human low dose oxycodone or methadone instead?


I'm on buprenorphine myself for opiate addiction. It helps stop my cravings and withdrawals. I am expected to slowly taper off this drug with time. So far, so good. Ironically it does not give me any sedation effects. Maybe it's different in animals?


My cat was diagnosed with cancer a couple weeks ago. She and her brother are 17-plus years old, both with kidney disease and hyperthyroidism (although, Max will live to be 40!)

I take morphine, for pain, too. I have no reaction to it and it appears Zoe doesn't either, but it works for her and it works for me!

I believe it all has to do with the dosage amount. Like with any drug, there needs to be adjustments, according to the reactions.


My cat just got the shot and her pupils are super dilated now. The vet said the shot would last for three days though, not 24 hours. So I wonder if her eyes will stay that way the whole three days. It is very worrying.


My vet gave me 12 syringes of 0.1cc/each of Buprenorphine for my cat, when she was spayed. After about an hour she was high as a kite. She definitely seemed to be feeling (or should I say feline, ha) no pain. She was lying on her back, all four legs outstretched with toes splayed. It was kind of funny in a sick sort of way! You can surely tell when it's wearing off, in about eight hours, as the cat starts to act "normal" again.


@ceilingcat - It is kind of funny to think of an animal being depressed (after all, what do they have to be depressed about) but I have a friend that has a dog on Prozac and it's really helped the dog. The dog was a rescue, and was very traumatized. The Prozac has helped the dog calm down and get more comfortable in his new home.


I always find it interesting when animals can take drugs that were originally designed for humans. However, buprenorphine isn't the only drug that works like this. My veterinarian prescribed Benadryl to my cat awhile ago, because the vet thought the cat might have allergies.

I've also heard that cats and dogs are sometimes prescribed Prozac or another anti-depressant that also works in humans if the vet thinks it will help their problems. I thought that was kind of funny.


@JaneAir - It was a probably a combination of both. If your cat was already sick and feeling tired, then with the medicine, I'm not surprised he was totally knocked out. At least he was under professional supervision at the animal hospital at the time.


@anamur - My cat has taken buprenorphine, but it was while he was at the animal hospital. I had to leave him there for an overnight stay, and he seemed to be really knocked out after they gave it to him. On the other hand, he was sick anyway, so that may have been part of it.

It's interesting your cat had the complete opposite reaction. I wonder why that happened. Also, hopefully the hyperactivity didn't affect whatever it was he was taking the medicine for in the first place.


@fBoyle-- My cat has been on buprenorphine a couple of times too and never had that side effect. He does become extremely hyper and active while on this drug though. It's really weird since it's supposed to make him sleepy.


@fBoyle-- What dose is your cat on? What is she being treated for?

I have heard of opiates causing this symptom on cats and since it happened after getting the buprenorphine, that is probably the cause. I would recommend keeping an eye on him and if his pupils don't go back to normal after the medication wears off, you might want to ask your vet.

Also, keep in mind that it can take opiates a long time to wear off and it's different with every cat. So I would give it twenty-four hours before getting worried. If additional symptoms show up though, do give your vet a call.


My cat was given a dose of buprenorphine at the vet's office this evening. I've noticed for the past few hours that his pupils are dilated.

Is this a side effect of this medication? Has anyone experienced this while their cat was on buprenorphine? Please help, I'm very worried.

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