Major Uses

Paroxetine is a selective serotonin reuptake inhibitor antidepressant. It increases the brain's serotonin levels to facilitate transmission of messages between cells in the brain. The medication works similarly to Prozac and is a useful tool when attempting to modify unacceptable behaviors in dogs and cats.

Paroxetine is not approved by the Food and Drug Administration for use in animals, but it is prescribed legally as an extra-label drug by veterinarians. It is most commonly used to treat phobias, aggression, separation anxiety, and compulsive disorders in dogs. In cats, this medication is primarily used to treat excessive fearfulness, aggression, urine-marking, and compulsive behaviors.

Common Precautions

The most common side effects associated with paroxetine use in animals include increased thirst, lethargy, tremor, and loss of appetite. Vomiting, diarrhea, hyperactivity, panting, irritability, anxiety, drowsiness, and dry or itchy skin are also possible. If seizures develop during treatment with paroxetine, the drug should be stopped and a veterinarian should be consulted.

Paroxetine should be used with caution in animals with kidney or blood disorders. Caution is also necessary when using in elderly animals and in those with a history of seizures.

Monoamine oxidase inhibitors (MAOIs), phenytoin, cimetidine, and L-tryptophan can interact with paroxetine and should not be used in animals undergoing treatment with the drug. Other drugs with a potential to interact with paroxetine include warfarin, encainide, flecainide, buspirone, tricyclic antidepressants, diazepam, lithium, haloperidol, phenylbutazone, and others.

Paroxetine should not be used in animals with a known allergy or hypersensitivity to the drug. Any known or suspected overdose should be reported to a veterinarian right away.


Paroxetine should be stored in a dry, cool place and at room temperature. It should be kept away from heat and direct sunlight and out of the reach of children and animals. Paroxetine should not be stored in the bathroom or above the kitchen sink. It may break down after exposure to moisture or heat.


Paroxetine is available as tablets in strengths of 20 mg and 30 mg.

The typical dose of paroxetine in dogs is 0.5 to 1 mg/lb (1 to 2 mg/kg) by mouth every 24 hours. In cats, the typical dose is 0.25 to 0.75 mg/lb (0.5 to 1.5 mg/kg) by mouth every 24 hours. Paroxetine may be given with food or on an empty stomach.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

If a dose of paroxetine is missed, it should be given as soon as possible. If it is almost time for the next dose, the missed dose should be skipped and the regular schedule should be resumed. Two doses of this medication should not be given at once.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.