Fluoxetine (Prozac) For Dogs: Safe Dosages And Uses (2024)

Leaving an anxious dog behind can be a terrible feeling for a pet owner, especially when their house is full of chewed up shoes and destroyed pillows upon return.

Pet anxiety isn’t all that uncommon. In a 2020 study, researchers in Finland surveyed dog owners and found nearly three-fourths (73%) of dogs had some kind of anxiety, with noise sensitivity being the most common trait, followed closely by fear.

Fortunately, there are treatments for anxiety in dogs, including medication like fluoxetine, an antidepressant that has effectively treated the symptoms of anxiety and other behavioral disorders in dogs.

And for most pet owners, the medication is covered by pet insurance.

Here’s a look at fluoxetine and whether it’s safe to give to your dog.

What Is Fluoxetine (Prozac) Used for in Dogs?

Similar to its use for humans, fluoxetine—also referred to by the brand name Prozac—is most commonly used to treat anxiety in dogs.

“Fluoxetine may be used to treat a number of behavioral disorders in dogs such as aggression, separation anxiety, phobias and compulsive behaviors,” says Dr. Jennifer Sperry, D.V.M., veterinary advisor for Pets Plus Us, a pet insurance company in Canada.

While treating a dog with fear, phobia, aggression or anxiety usually focuses on changing a dog’s emotional response with counterconditioning or reinforced-based techniques, sometimes it’s not enough on its own.

“Early intervention with medication may be necessary to achieve success and can be in the best interest of the fearful, anxious or phobic dog,” notes the Merck Veterinary Manual.

“The main benefits of using fluoxetine in dogs are the potential for improved behavior and reduced symptoms of anxiety or compulsive behaviors, leading to a better quality of life for the pet and its owners,” says Dr. Robert Gonzalez, D.V.M., regional medical director for Small Door Veterinary, a chain of veterinary facilities in the Northeast.

Is Fluoxetine Safe To Give to Dogs?

When given under the direction of your veterinarian, fluoxetine is safe to give to dogs.

“Fluoxetine can be a safe medication for dogs, but it is important to schedule an exam with your veterinarian before starting your dog on any new medication,” says Dr. Erica Thiel, D.V.M., Midwest area medical director for IndeVets, a nationwide veterinary staffing service.

Fluoxetine vs. Prozac

It’s important to note that fluoxetine is referred to by a variety of other names, which are branded names from different manufacturers of the same medication. While Prozac is one of the most common, other brand names for fluoxetine include Sarafem, Rapiflux and Selfemra.

Any use of these drugs in dogs is “off label” meaning they haven’t been approved for use in dogs by the FDA.

In 2022, the FDA did approve the medication Reconcile, which contains fluoxetine hydrochloride, for use with dogs. Reconcile is intended to treat separation anxiety in dogs along with behavior modification training.

Thiel notes that veterinarians still prescribe fluoxetine off-label instead of Reconcile “for a variety of reasons including ease of access (more pharmacies will carry these products over Reconcile), dosing options and occasionally due to cost concerns for the client.”

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When Owners Can Give Fluoxetine to Dogs

Fluoxetine should only be given to dogs if it has been prescribed by a veterinarian to help treat anxiety or behavioral issues.

Fluoxetine should only be given to your dog after you’ve taken them to the vet.

“Your veterinarian will check that your dog is healthy with no underlying conditions that would make it unsafe to give your dog fluoxetine,” Thiel says. “They will also verify that your dog is not taking any medication(s) that should not be administered with fluoxetine.”

When Owners Shouldn’t Give Fluoxetine to Dogs

It’s always best to talk to your veterinarian about all medications and supplements your dog is taking, as well as any known allergies when it comes to medications.

Fluoxetine should not be used in dogs for the following reasons:

• They are currently on or were recently on other antidepressants
• They have a history of seizures
• They are on a non-steroidal anti-inflammatory (NSAID), which can increase the risk of gastrointestinal bleeding
• They have a known allergy to fluoxetine or its components
• They are currently taking or have recently taken monoamine oxidase inhibitors (MAOIs), which can lead to potentially dangerous drug interactions
• They have severe liver or kidney disease

What is a Safe Fluoxetine (Prozac) Dosage For Dogs?

A safe dosage of fluoxetine will depend on several factors, including the dog’s size, weight, and its specific behavioral needs for the medication.

Fluoxetine is generally prescribed for dogs at 1 to 2 milligrams per kilogram (about 2.2 pounds) every 24 hours, according to the Merck Veterinary Manual.

The VCA Hospitals note that fluoxetine is available in tablet, capsule or liquid form, and can be given with or without food.

Can Dogs Overdose On Fluoxetine?

While fluoxetine is safe and approved by the FDA to treat anxiety in dogs, too much can lead to toxicity, according to the American College of Veterinary Pharmacists.

Dogs can overdose on fluoxetine, and may develop something called serotonin syndrome, Thiel says.

Sperry notes that “signs of serotonin syndrome can appear in as little as an hour or can take several days to develop.”

Symptoms of serotonin toxicity in dogs include:

• Fatigue
• Agitation
• Tremors
• Increased saliva production
• Vomiting
• Loss of appetite or refusal to eat
• Seizures
• Aggression
• Weakness
• Diarrhea
• Decreased heart rate
• Difficulty walking

If you suspect your dog has taken too much fluoxetine, it’s important you call your veterinarian right away.

Can I Give My Dog Fluoxetine Every Day?

Fluoxetine is intended for daily use and typically given to dogs every 24 hours

Fluoxetine Side Effects for Dogs

When taken as prescribed, fluoxetine should help ease wide fluctuations in mood such as fear and anxiety.

“In many cases, fluoxetine can help reduce anxiety and compulsive behaviors, leading to a calmer and more relaxed dog, Gonzalez says.“It can improve the dog’s overall quality of life by alleviating symptoms associated with behavioral disorders.”

But as is the case with most medications, fluoxetine does carry the risk of side effects.

The most common side effects for dogs taking the standard dose of fluoxetine include:

• Gastrointestinal upset
• Vomiting
• Diarrhea
• Appetite loss
• Lethargy
• Changes in sleep patterns

“Some dogs may also experience increased anxiety or aggression as an initial side effect before the medication starts to take effect,” Gonzalez notes. “It’s important to monitor your dog closely during the initial weeks of treatment for any concerning side effects.”

How Long Does it Take for Fluoxetine to Start Working?

Fluoxetine does not start working immediately.

“It generally takes about two weeks for fluoxetine to reach therapeutic levels in the body and start showing positive effects,” says Dr. Diana Watkins, D.V.M., owner of 143 Veterinary Services in Cohasset, Massachusetts.

In some instances, it can take 4 to 8 weeks for the full effects of fluoxetine to be seen in some patients, Thiel adds.

How Long Does Fluoxetine Stay in a Dog’s System?

How long fluoxetine stays in a dog’s system can vary depending on the dog’s overall health and metabolism, as well as how long the dog was on the medication.

Typically, fluoxetine stays in the body anywhere from a few days to a few weeks, Gonzalez says.

Thiel notes it’s important that owners not abruptly stop giving fluoxetine to their dogs, especially if they’ve been on the medication for a while. Dogs need to be slowly tapered off of fluoxetine.

“Sudden withdrawals can increase the risk of side effects, and even potentially worsen the undesirable behavior the dog was experiencing and put on fluoxetine for in the first place,” Thiel says.

Bottom Line

Under the proper care of a veterinarian, and in conjunction with a behavioral modification plan, fluoxetine can be used safely to treat and manage anxiety in dogs. Not only can it help improve your dog’s well-being and quality of life, but it can help improve yours as well.

If you think your dog may be a candidate for fluoxetine, it’s important to visit your veterinarian—only they can determine if the medication is appropriate for your dog.