Fluoxetine
Also known as: Prozac, Reconcile, Sarafem
- **Patience is Key:** This medication often takes 4 to 8 weeks to show its full effect. Do not stop giving it just because you don't see immediate results. - **Behavior Modification:** Fluoxetine is most effective when used alongside a behavior modification and training program recommended by your veterinarian. - **Side Effects:** The most common side effects include lethargy, decreased appetite, vomiting, shaking, restlessness, diarrhea, and excessive whining. If these are severe or persist, contact your veterinarian. - **Appetite Loss:** If your pet loses their appetite, try hand-feeding or temporarily increasing the palatability of their food (e.g., adding a little wet food or low-sodium broth). - **Do Not Stop Abruptly:** Do not discontinue this medication suddenly without your veterinarian's guidance, as it may cause withdrawal-like signs or a relapse in behavior. - **Seizure Warning:** Rarely, dogs may develop seizures while on this medication. If a seizure occurs, contact your veterinarian immediately. - **Tick Collars:** Inform your veterinarian if you use tick collars, as some contain amitraz, which can cause a dangerous drug interaction (serotonin syndrome) when combined with fluoxetine. - Keep this medication safely out of reach of children and other pets.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Adjunctive treatment of aggression
- To help control urine marking or separation anxiety
- To control pruritus when other therapies have failed
- Generalized anxiety disorder
- Urine spraying, psychogenic alopecia, and aggression
- Treatment of canine separation anxiety in conjunction with a behavior modification plan
- Separation anxiety and noise aversions
- Adjunctive pharmacological intervention for conflict-related aggression
- Compulsive disorders
- Adjunctive treatment of behavior disorders
- Adjunctive treatment of behavior disorders
- Separation anxiety, compulsive disorders, and aggression
How it is given
Possible side effects
- Anorexia or decreased appetite (common, often transient)
- Lethargy or depression
- Gastrointestinal upset (vomiting, diarrhea)
- Anxiety, irritability, or restlessness
- Insomnia or hyperactivity
- Panting (dogs)
- Changes in elimination patterns (cats)
- Paradoxical aggressive behavior (in previously unaggressive animals)
- Seizures (rare but possible)
- Lethargy
- Decreased appetite
- Vomiting
- Weight loss
- Trembling
Cautions & contraindications
- Known hypersensitivity to fluoxetine
- Concurrent use of Monoamine Oxidase Inhibitors (MAOIs), including selegiline and amitraz (found in some tick collars)
- Patients with epilepsy or a history of seizures
- Concurrent use with drugs that lower the seizure threshold (e.g., acepromazine, chlorpromazine)
- Known sensitivity to fluoxetine or other SSRIs
- History of seizures or epilepsy
- - **Seizure Disorders:** Use is contraindicated in patients with a history of seizures. - **Diabetes Mellitus:** Use with caution as fluoxetine may alter blood glucose levels, necessitating insulin adjustments. - **Hepatic Impairment:** Dosages may need to be reduced in patients with severe liver disease due to decreased clearance. - **Tapering:** Because of the long half-life of the active metabolite (norfluoxetine), tapering off the drug is generally only necessary when a patient has been on the drug long-term (>8 weeks). - **Pregnancy/Nursing:** Safety is not fully established (FDA Category C in humans). Excreted in milk at 20-30% of plasma levels; use caution in nursing animals.
Drug interactions
- BUSPIRONE: Increased risk for serotonin syndrome
- CYPROHEPTADINE: May decrease or reverse the effects of SSRIs (acts as a serotonin antagonist)
- DIAZEPAM, ALPRAZOLAM: Fluoxetine may increase diazepam and alprazolam plasma levels
- DIURETICS: Increased risk for hyponatremia
- INSULIN: May alter insulin requirements (can alter blood glucose)
- ISONIAZID: Increased risk for serotonin syndrome
- MAO INHIBITORS (e.g., amitraz, selegiline): High risk for serotonin syndrome; use contraindicated. A 5-week washout is required after stopping fluoxetine before starting an MAOI, and a 2-week washout if switching from an MAOI to fluoxetine.
- PENTAZOCINE: Serotonin syndrome-like adverse effects possible
- PHENYTOIN: Increased plasma levels of phenytoin possible
- PROPRANOLOL, METOPROLOL: Fluoxetine may increase these beta-blocker's plasma levels; atenolol may be safer to use
- TRAMADOL: SSRIs can inhibit the metabolism of tramadol to active metabolites, decreasing efficacy and increasing toxicity risk (serotonin syndrome, seizures)
Frequently asked questions
What is Fluoxetine used for in pets?
- **Patience is Key:** This medication often takes 4 to 8 weeks to show its full effect. Do not stop giving it just because you don't see immediate results. - **Behavior Modification:** Fluoxetine is most effective when used alongside a behavior modification and training program recommended by your veterinarian. - **Side Effects:** The most common side effects include lethargy, decreased appetite, vomiting, shaking, restlessness, diarrhea, and excessive whining. If these are severe or persist, contact your veterinarian. - **Appetite Loss:** If your pet loses their appetite, try hand-feeding or temporarily increasing the palatability of their food (e.g., adding a little wet food or low-sodium broth). - **Do Not Stop Abruptly:** Do not discontinue this medication suddenly without your veterinarian's guidance, as it may cause withdrawal-like signs or a relapse in behavior. - **Seizure Warning:** Rarely, dogs may develop seizures while on this medication. If a seizure occurs, contact your veterinarian immediately. - **Tick Collars:** Inform your veterinarian if you use tick collars, as some contain amitraz, which can cause a dangerous drug interaction (serotonin syndrome) when combined with fluoxetine. - Keep this medication safely out of reach of children and other pets.
Is Fluoxetine safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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