Does Prozac help aggressive cats? (+5 side effects)

In this article, we will discuss whether Prozac can be helpful in treating aggression in cats, how Prozac treats aggression in cats, what factors affect it and what are alternative treatment options available. We will also explore the tips to follow if a cat starts showing aggression.

Does Prozac help aggressive cats?

Yes, Prozac (fluoxetine) can be used to treat aggressive cats. However, it is not FDA-approved but Prozac is often prescribed off-label by veterinarians. Prozac is primarily known for its effects on humans for depression but it can also calm aggressive or anxious cats. 

Prozac is a selective serotonin reuptake inhibitor and by increasing the levels of serotonin in the body aggressive behaviours can be treated even in the felines like cats. 

If you want to administer Prozac to your cat then consult the veterinarian first. The response of a medication in a cat can also differ from one to another based on their physiology. Your doctor can help you determine the right dose and the right medication for your cat according to multiple factors. 

How does Prozac help aggressive cats?

Prozac works by increasing the levels of serotonin in the brain cells (1). Serotonin is the neurotransmitter that regulates mood, anxiety and aggression (2). When serotonin levels are low, cats may become more irritable and aggressive (3). By increasing serotonin levels, Prozac can help to improve their mood and behaviour and alleviate the symptoms of aggression.

Prozac has been shown to be effective in treating various types of aggression in cats (4)(5)(6). These include: 

  • Territorial aggression (aggression towards other cats or animals)
  • Fear-based aggression
  • Redirected aggression
  • Play aggression

In addition to reducing aggression, Prozac can also help improve other behavioural problems in cats such as anxiety, separation anxiety and destructive behaviour (7).

What are the factors that may influence Prozac treatment in cats?

Whether Prozac will help an aggressive cat depends on various factors.

Individual response: Cats, like humans, can have different responses to medication. Some cats may show a significant reduction in aggressive behaviour when given Prozac, while others may not respond as effectively.

Underlying cause: Aggression in cats can have serious underlying causes including fear, territorial behaviour or redirected aggression. Prozac is more likely to be effective if aggression is related to anxiety or fear.

Dosage: Veterinarians need to prescribe the right dosage regimen for Prozac to be effective for the cat. They need to determine the appropriate dosage and provide instructions for administration.

Duration: The duration of Prozac treatment can vary. In some cases, it may be a short-term solution to address a specific issue. While in others, it may be needed for an extended period. 

Diagnosis: Accurate diagnosis by a veterinarian is essential. A comprehensive evaluation of the cat’s behaviour triggers and overall health is needed to determine whether Prozac is an appropriate treatment.

Environmental modifications: Creating a cat-friendly environment that reduces stress, triggers and aggression is a critical part of treatment. Changes in the cat’s living space can significantly influence treatment outcomes. 

What other medications are used to treat aggressive cats?

Managing aggression in cats is often a multi-faceted approach that may include medications in addition to behavioural therapy and environmental modifications. Other than Prozac (fluoxetine), there is a list of other medications that can be used for the treatment of aggression in cats. These include (8):

  • Sileo
  • Clomipramine
  • Gabapentin
  • Buspirone
  • Diazepam
  • Lorazepam
  • Amitriptyline 
  • Mirtazapine
  • Cannabinoids
  • Behavioural Modification drugs like clonidine and propranolol

The choice of the drug depends upon the cat’s specific need and the type of aggression or any underlying condition. Medication should be used in conjunction with the behavioural therapy.

What are the potential side effects of using Prozac in cats?

Side effects of Prozac on cats are mild and usually go away on their own after a few weeks. However, it is important to monitor your cat closely for any side effects and consult the healthcare provider immediately. The side effects may include (7):

  • Gastrointestinal Upset such as vomiting, diarrhoea, decreased appetite.
  • Increased thirst and urination
  • Lethargy and weakness
  • Restlessness and anxiety
  • Behavioural changes such as hyperactivity
  • Skin reactions such as hair loss or itching
  •  Seizures (rare)

What to do if your cat shows aggression?

Here are steps to take if your cat shows aggression.

  • The first and foremost step is to consult your veterinarian to rule out any underlying cause of aggression.


  • Identify triggers. Observe your cat to determine what causes the aggressive symptoms to appear.


  • Behavioural therapy is the key component of addressing aggression in cats. This may involve desensitization, counter-conditioning and positive reinforcement techniques.


  • In some cases, medications may be necessary to manage aggression. The medications are only to be administered after a careful consultation with a veterinarian.


  • Create a cat-friendly environment that may minimize stress and triggers for aggression. This may include providing hiding spots, vertical space and designated resting areas.


  • Cats thrive on routine. Establish a consistent daily routine for feeding, playing and rest to reduce stress and anxiety.



In my opinion, Prozac can be used to treat aggression in cats but the doses are to be adjusted according to the cat. In the case of a cat, consulting the veterinarian is the most important step to take. The veterinarian can help with the correct evaluation and diagnosis of the cause and prescribe a treatment plan accordingly.



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