Fluoxetine

Fluoxetine: Uses, Dosage and Side Effects

Overview

• Fluoxetine and its primary metabolite, norfluoxetine, inhibit serotonin reuptake in the brain, leading to antidepressant effects and an increase in motor activity thresholds.
• Additionally, it inhibits noradrenaline reuptake to a minor degree, but it is regarded a specific serotonin reuptake inhibitor.

Uses of Fluoxetine

• Initially authorised as a veterinary product for the treatment of canine separation anxiety in conjunction with a behaviour modification plan.
• Also used for the treatment of a broader range of anxiety-related conditions, including compulsive disorders and some forms of aggression in dogs.
• Fluoxetine has been used to treat urinary discharge and other anxiety-related behavioural issues, such as psychogenic alopecia and certain forms of aggression, in cats.

Dose of Fluoxetine in Dogs and Cats

Dogs:

• 1–2 mg/kg p.o. q24h.

Cats:

• 0.5–1.0 mg/kg p.o. q24h.

Side Effects of Fluoxetine in Dogs and Cats

• Common side effects include lethargy, decreased appetite, and regurgitation, which may lead to a slight loss of weight.
• Also possible are trembling, restlessness, and other GI disturbances.
• The possibility of a medication-induced increase in aggression should be communicated to pet owners.

Contraindications of Fluoxetine in Dogs and Cats

• Known sensitivity to fluoxetine or other SSRIs, a history of seizures.

Some Notes:

• Fluoxetine and MAOIs (e.g. selegiline) should not be used within 2 weeks and 6 weeks, respectively.
• Fluoxetine, like other SSRIs, antagonises anticonvulsants and should not be used with epileptics or other seizure-lowering drugs like phenothiazines.
• When administered with aspirin or other anticoagulants, fluoxetine may increase tissue trauma-related bleeding.
• Should not be taken with other serotonergic drugs due to the risk of serotonin syndrome, but may be used with trazodone if the patient is closely monitored.