Sometimes, fear and anxiety can make it difficult for a cat to cope with her daily life. Perhaps there has been a change in the environment – a new cat or dog comes to live in the home or a new born baby comes home one day.

A diligent owner tries to adapt the environment to accommodate the cat and the newcomers.   Sometimes, the resident kitty remains upset, hiding under the bed and not the using the litter box regularly. 

So, off to the vet for kitty. The vet may prescribe a behavior medication for a cat to reduce anxiety and allow the cat to start to acclimate to the changes in her world (Reference 1).

Can Behavior Medication for a Cat Help?

Daily behavior medications may be prescribed for cats due to:

  • anxiety
  • fearful behavior or aggression
  • inter-cat aggression
  • urine marking
  • overgrooming due to anxiety or other psychological reasons

How Does a Daily Behavior Medication for a Cat Work?

Most of the daily drugs prescribed for feline behavior problems involve the neurotransmitter serotonin.

Serotonin is a neurotransmitter, a chemical that transmits signals from a nerve to another nerve, muscle cell or gland. In humans, serotonin regulates behavior, mood, memory and metabolic processes in the intestines (Reference 3). Serotonin is thought to perform a similar function in cats, inducing feelings of happiness and calmness.

The most common drugs used to treat feline behavior problems include:

  • fluoxetine (human analog is Prozac)
  • clomipramine
  • buspirone


Fluoxetine is a Sustained Serotonin Re-uptake Inhibitor (SSRI). It works by blocking the “reuptake” of serotonin, interfering with the metabolic “recycling” of serotonin and, consequently, serotonin actively transmits its messages for a longer period of time.

Time to full effect
Initially, there is an excess of serotonin due to the medication. Serotonin receptors are overwhelmed and you may see side effects such as decreased appetite and activity, and decreased grooming. But over 4-6 weeks, most of the receptors become less sensitive to the excess serotonin and the side effects abate (Reference 2).

Fluoxetine is the “go-to” daily behavior medication for a cat for most cases of feline anxiety, aggression, and house-soiling.


Clomipramine not only blocks the reuptake of serotonin, it also blocks reuptake of norepinephrine, a neurotransmitter responsible for the emotions underlying the “fight or flight” response. Most of the benefits of clomipramine are due to the action of serotonin, although norepinephrine also regulates anxiety and behavior.

Clomipramine has an antihistamine effect that contributes an additional calming effect similar to the sleepiness you may experience when taking allergy drugs such as benadryl.

Clomipramine reaches full effect in 4 weeks. There is more of a tendency toward side effects such as sedation, dry eye, dry mouth, urine retention, and constipation when compared with fluoxetine (Reference 2).

Clomipramine is typically used for canine separation anxiety and urine marking in cats. However, it has seen use to calm “bully” cats that pick on their more timid housemates (reference 4), due to its antihistamine effect.


Buspirone is another drug used in cat behavior. This drug binds directly to serotonin receptors to reduce anxiety and promote boldness (Reference 2).

Buspirone reaches full effect in 1-2 weeks. Cats on Buspirone are more friendly and socially assertive. Because the drug promotes boldness, it can make aggressive cats more aggressive. It is primarily used to treat fearful, non-aggressive cats for urine marking and in cases of inter-cat aggression (Reference 2).  Victim cats on buspirone are bolder and are less likely to behave like “prey” when around more aggressive cats.

How do I know if the drug is working?

To determine if the drug is working, you must “measure” the behavior regularly and compare it to the behavior you observed before starting the medication (Reference 1).

Before Starting the medication

  • Identify the problem behavior.
  • What are the characteristics of the problem?
  • How often does this occur?
  • Where does it occur?
  • Can you assign an intensity to the behavior? 10 for very intense, 0 for calm, relaxation?
  • How long does an episode last – how long before the cat becomes calm again?

It can be helpful to draw a house map and note on it where the behavior occurs.

House Map
A house map showing areas where house-soiling has occurred.

Once the medication starts…

Maintain a daily diary of the behavior. Look for trends showing that the behavior is not as frequent, not as intense or prolonged (Reference 1).

Keeping a Diary

Back to our cat who had her world turned upside down with a new dog or baby. She is hiding and not always using her litter box.



The owner can record how often and/or how long the cat hides under the bed.


In this case, monitoring involves checking the house for soiled areas and noting if the cat has soiled these areas.

The number of house-soiling/hiding incidents should decline if the drug is working once there has been enough time for it to reach full effectiveness.

Serotonin Syndrome

Too much serotonin can be fatal. Watch out for:

  • accidental overdose
  • combining two or more medications that act on serotonin
  • combining supplements that boost serotonin levels with medications such as fluoxetine, clomipramine and buspirone.

Signs of serotonin Syndrome

  • agitation, restlessness, aggression
  • tremors, ataxia, seizures, coma
  • vomiting, diarrhea, lack of appetite

Seek emergency treatment immediately if your cat takes a behavior drug and you see these signs!

A daily behavior medication for a cat can help reduce anxiety and aggression to a level where the owner can start a behavioral modification program. Even in cases where the owner is already following a behavioral modification program, medication can help improve the effectiveness of the program. These drugs, under a veterinarian’s supervision, are safe and can improve feline welfare. Maintaining a daily diary of behavior incidents is an important part of assessing the drug’s efficacy.


  1. Denenberg S, Dubé MB. Tools for managing feline problem behaviours: Psychoactive medications. Journal of Feline Medicine and Surgery. 2018;20(11):1034-1045. doi:10.1177/1098612X18806760
  2. Herron, M. Integrated Care: Feline Psychopharmacology, Nutrition, & Supplements. Presented at: 2022 American Association of Feline Practitioners Conference, Pittsburgh, Pennsylvania. October 27-30, 2022
  3. Bamalan OA, Moore MJ, Al Khalili Y. Physiology, Serotonin. [Updated 2023 Jul 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from:
  4. Capuzzi, Joan. Medicine to Ease the Feline Mind. dvm360.February 2023 Vol. 54 , Issue 2, p. 16 January 4, 2023. Viewed 5/2024.
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