Fluoxetine for Dogs Can Help Pups With Anxiety—Here's How It Works
It's hard to watch your dog experiencing anxiety. It can be even worse if your dog's anxiety is manifested through chewed-up shoes and scratching holes in doors. But there's good news: There are medications that can help.
Many of us might be reluctant to give our pets antidepressants for fear causing negative side effects—I certainly had concerns when I started my own dog on the antidepressant fluoxetine. But medications including fluoxetine for dogs play an important role in managing certain behavioral concerns in our pups.
To better understand how fluoxetine can help dogs, we spoke with Leslie Sinn, DVM, DACVB, and a member of the Daily Paws Advisory Board. She says she uses fluoxetine every day in her behavior practice and has had a lot of success.
What Is Fluoxetine?
Fluoxetine, often known by its brand name, Prozac, is a selective serotonin reuptake inhibitor (SSRI) often used to treat anxiety and depression disorders in humans. But fluoxetine is used in dogs, too, for reducing anxiety and the undesirable behaviors that come with it.
Serotonin is a neurotransmitter (that is, a type of chemical messenger) that plays an important role in many bodily functions, including mood and behavior, digestion, sleep, and pain perception. SSRIs such as fluoxetine act on serotonin receptors in the brain, delaying the reuptake of serotonin, thus allowing serotonin to remain in the brain longer. It's believed that serotonin promotes a general sense of well-being and happiness, so drugs that enhance serotonin often combat feelings of anxiety and depression.
When it was first introduced in the late 1980s, fluoxetine immediately became known as a breakthrough drug for depression. Its use quickly expanded to treat other conditions, such as anxiety, and it wasn't long before veterinarians began to prescribe it for dogs. In 2007, the FDA approved Reconcile, a veterinary brand of fluoxetine, for the treatment of separation anxiety in dogs.
What Is Fluoxetine Used for in Dogs?
Sinn tells Daily Paws that fluoxetine has been proven effective to treat separation anxiety, but vets have successfully used the drug "off-label" to treat anxiety and compulsive disorders in dogs.
"It's been on the market so long that, even though we may not have an official FDA approval for these alternative uses, there's enough second-tier information out there to justify its use—case reports, case studies, retrospective studies," Sinn explains. "There's a variety of situations where it would be appropriate to use … everything from fear-based aggression to noise sensitivity and phobias."
There's plenty of evidence that fluoxetine helps humans, and people taking fluoxetine can communicate their experiences and whether the medication has helped. But with dogs, we must observe their behaviors because pups can't tell us how they feel. So, if your veterinarian recommends fluoxetine for your dog, it's important to work closely as a team during treatment.
Is Fluoxetine Right for Your Dog?
If your dog is suffering from anxiety, your vet may recommend a trial of fluoxetine—a concept that makes some pet parents hesitate. "Most people come into our practice with strong reservations about 'drugging' their dogs," Sinn says. "There's still a pretty strong stigma about using medication."
But what some people may not realize is that anxiety, fear, and worry all lower a dog's threshold for other stimuli. This explains why it's difficult to get your dog's attention when he's extremely anxious. The same is true for people—if you're trying to perform a task but are dealing with mental stress, that task is going to be much more difficult. So, it's very difficult to teach a dog with severe separation anxiety that there's nothing to fear when he's left alone.
Sinn stresses that the purpose of medications like fluoxetine is not to sedate the dog or change their personality. Rather, the goal is to:
- Raise the dog's threshold so they're less likely to react to the provocative stimulus
- Decrease anxiety and worry
- Make it easier to interrupt and redirect the dog
"That allows you to get your foot in the door so that behavior modification is effective," Sinn says. And behavior modification is the key to ultimately helping your dog—fluoxetine alone will not stop unwanted behaviors. As Sinn explains, "anybody who expects us to be able to dispense a purple pill and magically fix everything is engaging in wishful thinking."
It also takes some time for fluoxetine to start working (about six to eight weeks), so patience is a must. Sinn adds that, in her experience, the changes continue over quite a period of time, sometimes years. After taking fluoxetine for about two months, pet parents can begin specific behavior modification as recommended by a veterinary behaviorist or certified animal behavior consultant.
Fluoxetine Dosage for Dogs
Each dog responds differently to fluoxetine and will have different dosing needs. The generally recommended dosage range is between 1–2 milligrams per kilogram of body mass, once daily. In order to avoid side effects and establish the best therapeutic dose, Sinn says she starts patients on a low dose of fluoxetine and gradually increases it.
Fluoxetine is typically given by mouth as a pill or liquid, but transdermal applications may be available for dogs who don't take medication well. You will need a prescription from your vet to purchase fluoxetine, which should be available at most pharmacies.
Fluoxetine Side Effects in Dogs
When my own dog started taking fluoxetine, she became lethargic and stopped eating within a few days, and we stopped treatment. I've heard similar stories about this happening with other dogs, but it turns out that these pups may have been on doses that were a bit too high. That's why Sinn recommends starting off low and slow and seeing how the pet responds to the medication.
Side effects of fluoxetine in dogs are pretty minimal, Sinn says, but can include:
"Every now and again, you will run into an individual that reacts very strongly to the medication and has issues," she says. "They may get jittery or they may stop eating entirely, even on a really low dose. Then obviously, that particular medication is not right for the pet."
Contact your vet if your dog is experiencing any side effects from fluoxetine. The dose may need to be adjusted under your vet's supervision.
Precautions and Warnings
Before starting a new medication, your veterinarian may recommend lab work to assess your dog's overall health and look for any underlying conditions. The first goal is to rule out physical conditions that are causing behavioral concerns, such as pain (which is known to exacerbate anxiety). Lab tests may also reveal a condition that could be worsened by the medication. For example, fluoxetine is metabolized by the liver, so this medication should be used with caution in dogs with liver disease.
Sinn says that certain medications should be used cautiously in conjunction with fluoxetine, including tramadol, trazodone, and antifungal drugs. Be sure to tell your vet about all medications and supplements that your dog gets.
Sinn also warns of a condition called serotonin syndrome that is associated with SSRI treatment. While this is more common in dogs after an accidental overdose, it can technically occur even when the drug is dosed properly. This is yet another reason why it's so important to stay in touch with your vet about your dog's progress while taking fluoxetine.