What is the information about fluoxetine (Prozac)?

From the Guidelines

Fluoxetine is a recommended treatment option for major depressive disorder, with a standard starting dose of 20 mg once daily, and treatment duration varying based on the condition but often continuing for at least 6-12 months after symptom improvement for depression. The American College of Physicians recommends that when clinicians choose pharmacologic therapy to treat patients with acute major depression, they select second-generation antidepressants, including fluoxetine, on the basis of adverse effect profiles, cost, and patient preferences 1. Fluoxetine works by increasing serotonin levels in the brain by blocking its reabsorption, which helps regulate mood. Common side effects include nausea, headache, insomnia, drowsiness, and sexual dysfunction. It may take 4-6 weeks to experience the full therapeutic benefits. Patients should not stop taking fluoxetine abruptly as this can cause withdrawal symptoms, and should always consult their healthcare provider before making any changes to their medication regimen.

Some key considerations when prescribing fluoxetine include:

• Starting with a subtherapeutic dose as a “test” dose to assess for initial adverse effects such as anxiety or agitation 1
• Gradually increasing the dose as tolerated within the therapeutic dosage range, with faster up-titration potentially indicated for more severe anxiety presentations 1
• Monitoring for symptoms, especially in the first 24 to 48 hours after dosage changes, and being cautious when starting the second non-MAOI serotonergic drug at a low dose 1
• Being aware of potential drug-drug interactions, particularly with monoamine oxidase inhibitors (MAOIs) and drugs that prolong the QT interval 1

In terms of treatment outcomes, fluoxetine has been shown to be effective in producing depression remission, with a response rate similar to other second-generation antidepressants 1. The American College of Physicians recommends continuing treatment for 4 to 9 months after a satisfactory response in patients with a first episode of major depressive disorder, and an even longer duration of therapy may be beneficial for patients who have had 2 or more episodes of depression 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Overview of Fluoxetine

• Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) with demonstrated efficacy in the treatment of major depressive episodes 2, 3.
• It has been evaluated for the treatment of obsessive-compulsive disorder (OCD) since 1985, with studies showing its effectiveness in reducing symptoms of OCD 2, 4, 5.

Efficacy in Obsessive-Compulsive Disorder

• Fluoxetine has been found to be effective in OCD in all published open-label studies and placebo-controlled trials, with an effective dose range of 40 to 60 mg daily 2.
• Clinical evaluation was carried out using specific scales such as the Y-BOCS or NIMH-OC, and improvement was observed after several weeks of therapy 2.
• A comparison of fluoxetine and clomipramine showed comparable efficacy and a superior safety profile, both in terms of anticholinergic side effects and cardiotoxicity or overdosage 2.

Efficacy in Major Depressive Disorder

• Fluoxetine has been shown to be effective in the treatment of major depressive disorder, with a therapeutic response time of 15-20 days 3.
• Meta-analyses have confirmed that fluoxetine is as effective as tricyclic antidepressants and appears more effective than placebo in improving symptoms of depression 3.
• Fluoxetine has a more favorable tolerability profile compared to tricyclic antidepressants, with a lower toxicity profile 3.

Side Effects and Safety Profile

• Common side effects of fluoxetine include gastrointestinal disturbances, headache, sedation, insomnia, activation, weight gain, impaired memory, excessive perspiration, paresthesia, and sexual dysfunction 6.
• Fluoxetine has been found to have a good safety profile, with adverse effects rarely leading to discontinuation of treatment 2.
• However, rapid increase in fluoxetine dose to high doses has been associated with depressive symptoms in some patients 4.