Does Prozac Help an Aggressive Cat?

"Aggressive? No, I'm quite a mellow fellow. How did that happen?"
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If Fluffy's aggression makes life miserable for you or for his fellow feline residents of your household, medication and behavioral therapy could save the day. Your vet might prescribe Prozac, one of the best-known antidepressants used in people. If it works on your cat, peace could be restored in your home.


Prozac is a brand name for fluoxetine, which is also marketed for cats under the name Reconcile. Fluoxetine is a "selective serotonin reuptake inhibitor," which means it increases levels of serotonin in your cat's central nervous system.

It won't work overnight -- it could take as long as month before you'd see a difference in your cat's behavior. As the serotonin accumulated in his system, he'd gradually become calmer and better able to cope with the things that trigger his aggression.


Aggression in cats takes many forms. Fluffy's aggression could be directed against a certain person in your home, against specific felines or canines, or against just about everybody. You could be at your wit's end with his behavior, but don't give up without attempting treatment.

Your vet can help diagnose the roots of his behavior. It's important to keep detailed accounts of your cat's behavior. Do you notice something triggering his aggressive responses, or do they appear out of the blue?

Although fluoxetine can help reduce aggressive behavior, it's not a cure-all unless accompanied by behavioral modification. Don't yell at the cat or hit him; that would only make him fearful. DVM 360 recommends placing an aroused cat in a darkened room and closing the door until he calms down. Wear gloves to protect yourself when moving him.

Side Effects and Contraindications

The most common side effect of fluoxetine is sleepiness, something you probably don't mind in an aggressive feline. But more serious side effects are possible. These include appetite loss and behavioral changes. Although the idea of giving fluoxetine to Fluffy is to make him less aggressive, in certain cats the drug actually increases aggression.

If your cat accidentally receives too much of the drug, he might start salivating heavily and become very restless and agitated. The response to an overdose occurs within a hour, so you'd notice symptoms quite quickly. Take your cat to the vet for treatment.

Cats diagnosed with diabetes, liver disease or epilepsy should not receive fluoxetine.

Other Uses

Treating aggression isn't the only reason your vet might prescribe Prozac for Fluffy. It's also used for separation anxiety, which doesn't occur that frequently in felines; and for urine marking, which does.

If your cat decides the whole house is his litter box, his behavior could be related to aggression. He might be marking territory with his urine spraying, letting other animals -- or people -- know that he's in charge of that turf. Prozac can help disabuse him of that notion and get him back to the litter box.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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