By Rania Gollakner, BS, DVM, MPH

What is fluoxetine?

Fluoxetine (brand names: Prozac®, Reconcile®, Sarafem®) is an SSRI antidepressant used to treat a variety of behavioral disorders in dogs and cats. The FDA approved form for dogs is labeled to treat separation anxiety.

Its use in cats, dogs, and birds to treat certain behavioral conditions is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

How is fluoxetine given?

Fluoxetine is given by mouth in the form of a tablet, capsule, or liquid. It may be given with or without food, but if your pet vomits when dosed on an empty stomach, give future doses with a meal or a treat. Measure liquid forms of this medication carefully. Do not stop this medication abruptly unless instructed by your veterinarian. Do not give this medication in conjunction with flea/tick collar use. Do not give aged cheeses to your pet while using this medication.

This medication can take up to a few weeks before full effects are noted, and at times improvement may not be visibly obvious. Laboratory tests may be needed to evaluate this medication’s effectiveness.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

The most common side effects include sleepiness and decreased appetite. Other side effects include vomiting, diarrhea, shaking, restlessness, panting, whining/vocalization, incoordination, hypersalivation, and weight loss. Serious/severe side effects include seizures, aggression, and excessive/persistent vomiting. In cats, behavior changes such as anxiety, irritability, lack of appetite, diarrhea, and changes in sleep and bathroom use.

This moderate-acting medication should stop working in a few days, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Fluoxetine should not be used in pets with a history of seizures or in pets that are on medications that lower the seizure threshold. It should not be used in pets that are allergic to it, pets taking MAOIs, pets younger than 6 months of age, or aggressive pets. Use cautiously in pets with diabetes mellitus, severe liver disease, or in pregnant or lactating pets.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with fluoxetine: anticoagulants, aspirin, buspirone, cyproheptadine, diazepam, alprazolam, diuretics, flea/tick collars, insulin, isoniazid, monoamine oxidase inhibitors (MAOIs), methadone, NSAIDs, pentazocine, phenytoin, propranolol, metoprolol, St. John’s wort, tramadol, tricyclic antidepressants (TCAs), or trazodone.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working. Monitor your pet for serious/severe side effects.

How do I store fluoxetine?

Store this medication in a tightly closed container at room temperature between 68°F and 77°F (20°C and 25°C). Protect from moisture and light. For compounded forms of this medication, follow the directions on the label.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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