Is cyclobenzaprine safe for dogs?

When under a vet’s supervision, this human prescription medication can help some pets

By Rebecca Rovenstine | Nov. 29, 2022 Medically reviewed by Emma Ryan, DVM

Can dogs take cyclobenzaprine? | Cyclobenzaprine dosage for dogs | Side effects | Safety

If you’ve ever sprained your ankle or strained a muscle, you might be familiar with the medication cyclobenzaprine. Cyclobenzaprine, sold under the brand name Flexeril or Fexmid, is a prescription drug and muscle relaxant that manages muscle spasms and blocks pain by inhibiting nerve impulses being transmitted to the brain. While this drug is often prescribed to humans, you may be surprised to learn that it may also be prescribed to your furry friend.

What is cyclobenzaprine used for in dogs?

Cyclobenzaprine is not licensed to be used in dogs, but is occasionally used off label under supervision by a veterinarian.

“Dogs can experience muscle spasms just as human patients can and in appropriate doses, cyclobenzaprine can be quite safe and effective for our canine friends,” explains Crystal A. Riley, Pharm.D., lecturer of health administration at Robert F. Wagner Graduate School of Public Service.

Dogs may also be prescribed cyclobenzaprine for high pain levels, like in cases of severe arthritis or a bulging disc. However, pain relievers like NSAIDs are more commonly used in these cases if a dog can tolerate it. If not, the muscle relaxer methocarbamol is more commonly prescribed to dogs when compared to cyclobenzaprine.

How much cyclobenzaprine can I give my dog?

How much cyclobenzaprine your dog is prescribed will depend on the size of your animal.

Cyclobenzaprine comes in a tablet or extended-release capsules. Your veterinarian will determine the form of drug your dog takes. If your dog is a picky eater, there are meat-flavored pill pockets that may help entice your dog into taking it, but hiding the pill in your pet’s favorite food is also a good trick.

While humans take 10 mg of cyclobenzaprine, this would be much too high of a dose for your pet so following your vet’s instructions on dosage is very important.

Cyclobenzaprine for dogs side effects

Since cyclobenzaprine is less commonly used in animals, it is important to closely watch your dog for any signs of side effects. According to Lisa Steinberg, DVM, a veterinarian working at veterinarians.org, common side effects include:

Excess salivation or dry mouth
Lethargy
Weakness
Tremors or ataxia
Loss of balance
Depressed mental activity
Seizures
Coma
Low body temperature
Low heart rate
Abnormal blood pressure

These side effects will typically happen within the first hour of ingestion and will wear off after a few hours. For any of the more serious side effects, it is important to seek medical attention for your pet right away as they can be a sign of an overdose.

Is cyclobenzaprine safe for dogs?

Cyclobenzaprine is a bit controversial in the veterinarian world. Some vets are comfortable prescribing this drug, while others are less so. For most dogs, it’s safe when under the supervision of a vet and when your dog is monitored closely for side effects.

However, Dr. Steinberg says: “Cyclobenzaprine is not generally considered safe in dogs, and most veterinarians will not prescribe it. For this reason, there is no established safe dose for dogs, as administration can lead to toxicosis.”

There are very limited studies about the use of cyclobenzaprine in dogs, with only a few papers written in the ‘70s and ‘80s. Because of this, it is important to talk with your dog’s veterinarian about using cyclobenzaprine for their specific situation.

If your vet does prescribe cyclobenzaprine to your canine, be sure to monitor them after ingestion for any potential side effects.