Paroxetine (Paxil) for Dogs: This Medication Can Help With Anxiety and Compulsive Disorders

You may be familiar with paroxetine (Paxil) from its use in human medicine. But veterinarians also use this medication to treat some behavioral conditions in dogs.

Read on to learn more about paroxetine, including how and why it’s used and what precautions you should take when giving this medication.

Paroxetine (Paxil) for dogs at a glance

What is paroxetine for dogs and how does it work?

Paroxetine is an antidepressant that is used in both human and veterinary medicine. 

Paroxetine is a selective serotonin reuptake inhibitor (SSRI). These medications slow the rate at which serotonin (a neurotransmitter) is cleared from the brain. This leads to increased serotonin levels within the brain, which can have multiple benefits. 

What is paroxetine used for in dogs?

Paroxetine is often used to treat anxiety. Anxiety in dogs can take many forms, ranging from separation anxiety to generalized anxiety disorder. Fear aggression is also a form of anxiety, and it is often treated with paroxetine. 

Veterinarians also use paroxetine to treat compulsive behaviors in dogs. Examples of compulsive behavior may include: 

• Lick granulomas

• Pacing

• Circling

• Chasing invisible or unseen items

• Excessive licking or chewing

How is paroxetine given to dogs?

Your veterinarian will calculate the best paroxetine dose for your dog. The dose is based on your dog’s body weight and the condition being treated. Lower doses are often used for anxiety, while compulsive behavior may be treated with higher doses.

Paroxetine is given by mouth once or twice daily. It is usually given as a tablet or capsule, though it may also be available as a liquid suspension.

You can give this medication with or without food. Giving the medication with food may decrease the risk of gastrointestinal side effects. 

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What are the common side effects of paroxetine in dogs?

Dogs taking paroxetine may have gastrointestinal side effects such as: 

• Decreased appetite

• Nausea

• Vomiting

• Diarrhea

You can reduce the risk of gastrointestinal effects by giving paroxetine with food. If your dog develops gastrointestinal signs, contact your veterinarian for advice. 

What are the most serious risks of paroxetine for dogs?

Paroxetine should not be stopped suddenly. If you must stop giving your dog this medication, talk to your veterinarian about how to taper it safely. Suddenly stopping paroxetine may cause: 

• Anxiety

• Agitation

• Irritation

• Restlessness

• Lethargy

If these effects occur, contact your veterinarian. You may need to resume your dog’s paroxetine dosing, then gradually taper to wean them off the medication. 

Paroxetine and serotonin syndrome

Paroxetine works by increasing levels of serotonin in the brain. Serotonin syndrome can occur when paroxetine is combined with other medications that also increase serotonin levels. This condition can be fatal in dogs. 

Signs of serotonin syndrome in dogs include:

• Agitation

• Excitation

• Restlessness

• Vocalizations 

• Increased heart rate

• Dilated pupils

• Muscle tremors 

• Fever 

• Seizures

Serotonin syndrome is a medical emergency. If your dog shows signs of serotonin syndrome, seek veterinary care immediately. If your veterinarian’s office is closed, contact your local veterinary emergency hospital. 

Does paroxetine interact with any other dog medications?

Paroxetine can interact with a variety of other medications. Be sure your veterinarian knows all the medications your dog is taking. This includes prescription medications, over-the-counter medications, and supplements. 

Medications that may increase the risk of serotonin syndrome when combined with paroxetine include: 

• Chlorpheniramine (an antihistamine) 

• Clomipramine

• Dextromethorphan

• Ephedrine

• Fluoxetine

• Morphine

• Pseudoephedrine

• Selegiline and other monoamine oxidase (MAO0 inhibitors 

• St. John’s wort 

• Tramadol 

• Trazodone

Other medications that may increase the risk of side effects when combined with paroxetine include: 

• Aspirin

• Nonsteroidal anti-inflammatory drugs (NSAIDs)

• Sedatives

• Warfarin

What should you do if your dog misses a dose of paroxetine?

If your dog misses a dose of paroxetine, give the missed dose as soon as you remember to do so. If it is almost time for your dog’s next dose, skip the missed dose and resume your dog’s regular dosing schedule. Do not give a double dose of paroxetine.

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Written by:

Catherine Barnette, DVM

Catherine Barnette, DVM, is a small animal veterinarian with 14 years of experience providing preventive care, medical workups, and surgical services in a number of general veterinary practices. She also served on her county's board of health for several years and taught biology laboratories for college students.

Edited by:

Renée Fabian, MA

Renée Fabian is the senior pet health editor at GoodRx. She’s worked for nearly 10 years as a journalist and editor across a wide range of health and well-being topics.

Reviewed by:

Ghanasyam Bey, DVM

Ghanasyam Bey, DVM, is from Cleveland, Ohio, and attended Princeton University for undergraduate studies. After a year of biology research at Duke University, he attended Ohio State College of Veterinary Medicine.

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