Buprenorphine (Buprenex) For Cats and Dogs: What Are The Side Effects and Alternatives?

Medically reviewed by Nicole Wanner, DVM

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Buprenorphine (also known as Buprenex) is a pain reliever commonly used in cats and dogs experiencing mild to moderate pain. It is often prescribed to manage pain after surgery or an injury, especially for cats.

It is a type of analgesic (a medication that provides relief from pain without putting your pets to sleep or making them lose consciousness) used primarily to help manage and dull pain.

Buprenorphine is not an over-the-counter drug; a veterinarian must prescribe it.

While this drug is less dangerous than some other opioid medications, it can still have side effects and should be used carefully.


Buprenorphine is used in lower doses; since in higher doses, your pet may experience a “ceiling effect,” which means giving more of this drug does not create a more significant effect.

This is a potent drug, always give the exact amount that your vet has prescribed. Your pet should have a physical exam and lab work done before considering using this drug.

In cats, it is used by applying inside of cheek pouch or under the cat’s tongue. The drug is absorbed into the body directly from the mouth membranes making swallowing unnecessary.

In dogs, it is typically administered via intravenous injection (into a vein) or under the skin. When given orally, this drug doesn’t work as well as in cats. If you are asked by your vet to provide injections of this drug at home, make sure you follow your vet’s instructions carefully.


Sedation (sleepiness) is the most common side effect of Buprenorphine, but other side effects may include:

Cats Dogs
Dilated pupils Agitation
Excessive licking Constricted pupil
Gastrointestinal side effects Slow heart rate
Pacing Drop in blood pressure
Rubbing Lower Body Temperature
Slow breathing

The most potentially serious side effect of buprenorphine is slowed breathing. This side effect is more likely when buprenorphine is used in a surgical setting by veterinarians, but it is also something to watch for in animals given the medication at home. If your dog or cat takes buprenorphine and you have concerns about slow breathing, contact your vet’s office.

Buprenorphine is broken down by the liver and intestinal lining in dogs and cats. Therefore, pets with liver disease may eliminate this drug more slowly and experience prolonged effects.

Your vet will help determine whether buprenorphine is safe for your pet. Buprenorphine is used with extreme caution or avoided in dogs and cats with the following conditions:

  • Severe liver disease
  • Severe respiratory issues (including from heart failure or head trauma)
  • Hypersensitivity or allergy to opioids

Buprenorphine should also be used with caution in pets with:

  • Addison's Disease
  • Central nervous system (brain and spinal cord) dysfunction
  • Heart or lung problems
  • Very young, very old, or very sick/weak animals
  • Hypothyroidism (low thyroid levels)
  • Liver problems


According to Drugs.com, the average cost for Buprenex (injectable solution) is around $89 for 5 milliliters worth of supply. However, the price will vary depending on your veterinarian and/or the pharmacy where you pick up the medication.


Some medications may interact with Buprenorphine. Be sure to let your vet know all the medicines your pet is taking.

Most medication interactions either increase or decrease a drug’s effectiveness. The drugs listed below may interact with buprenorphine:

Drug Drug
Anticonvulsants Antihistamines
Azole antifungals Barbiturates
Benzodiazepines Central nervous system depressant agents
Cisapride Cyclobenzaprine
Desmopressin Erythromycin
Fentanyl MAOIs (certain antidepressants)
Metoclopramide Pancurnium
Naloxone Tramadol
Rifampin Tranquilizers
Mirtazapine fluoxetine


Your vet may prescribe medications such as Buprenorphine to manage your pet's pain. Although Buprenorphine is very effective, it can also have dangerous side effects.

Some studies have shown that CBD may have the potential to assist with certain types of chronic pain.

CBD has the potential to help your pet manage their discomfort, but diagnosis and advice on treatment should always come from your vet.





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