Fluoxetine HCl Capsule

Fluoxetine HCl Capsules are a prescription selective serotonin reuptake inhibitor (SSRI) — the same active ingredient as Prozac and the veterinary brand Reconcile — used in dogs and cats to help manage anxiety-related behavior problems. In dogs, fluoxetine is best known for treating separation anxiety alongside a behavior-modification plan; in cats it is commonly prescribed for urine marking, fear-based aggression, and compulsive over-grooming. Capsules are available in 10 mg, 20 mg, and 40 mg strengths.

Key facts

• Active ingredient: fluoxetine hydrochloride 10 mg, 20 mg, or 40 mg per capsule
• Species: dogs and cats
• Drug class: selective serotonin reuptake inhibitor (SSRI)
• Available sizes: single capsules up to 100-count supplies in each strength
• Form: oral capsule, given once daily
• Typical uses: separation anxiety, generalized anxiety, fear-based aggression, compulsive behaviors, feline urine marking
• Prescription status: requires authorization from your veterinarian

How to use

Fluoxetine is given by mouth once daily, with or without food; your prescribing veterinarian determines the dose for your pet's weight and condition. Expect 4–8 weeks of consistent daily dosing before the full effect is seen, and pair the medication with a behavior-modification plan for the best results. Do not stop fluoxetine abruptly after long-term use — your veterinarian will advise a gradual taper.

Safety information

The most common side effects are decreased appetite, lethargy, and mild stomach upset, which usually resolve within the first couple of weeks. Contact your veterinarian if you see restlessness, agitation, or worsening behavior. Do not combine fluoxetine with MAO inhibitors such as selegiline or amitraz, and use caution with other serotonergic drugs (trazodone, tramadol) because of the rare risk of serotonin syndrome. Use carefully in pets with a history of seizures, and keep the capsules well out of reach of pets and children.

Frequently asked questions

How does fluoxetine work in dogs and cats?

Fluoxetine increases the availability of serotonin in the brain, which helps reduce anxiety and reactivity so pets can respond to training and behavior modification.

How long does fluoxetine take to work?

Some improvement may appear within 1–2 weeks, but the full effect typically takes 4–8 weeks of consistent daily dosing.

Is pet fluoxetine the same as Prozac?

Yes — generic fluoxetine contains the same active ingredient as human Prozac and the FDA-approved veterinary brand Reconcile, dosed appropriately for pets.

What are the common side effects of fluoxetine?

Reduced appetite, lethargy, and mild GI upset are most common early on and usually fade; tell your veterinarian if agitation or worsening behavior appears.

Is a prescription required for fluoxetine?

Yes. Fluoxetine is a prescription medication that must be authorized by your veterinarian based on a current veterinarian-client-patient relationship.

Where can I buy fluoxetine capsules?

Order through our Vetcove pharmacy store, which ships from our home pharmacy and offers Autoship savings.

Prefer a tablet? See Fluoxetine Tablets, or read our guide, What You Need to Know About Fluoxetine.