From the Guidelines
Discontinuing fluoxetine (Prozac) can lead to a discontinuation syndrome characterized by dizziness, fatigue, lethargy, and other symptoms, especially when stopped abruptly, and a gradual tapering of the dose is recommended. The effects of discontinuing fluoxetine can vary depending on the individual and the duration of treatment. According to the clinical practice guideline for the assessment and treatment of children and adolescents with anxiety disorders 1, a discontinuation syndrome has been reported following missed doses or acute discontinuation of shorter-acting SSRIs, notably paroxetine but also (to a lesser extent) fluvoxamine and sertraline.
Some key points to consider when discontinuing fluoxetine include:
- The risk of discontinuation syndrome is higher when stopping shorter-acting SSRIs abruptly, and fluoxetine, being a longer-acting SSRI, may have a lower risk of discontinuation syndrome compared to paroxetine or fluvoxamine 1.
- A conservative approach to discontinuing fluoxetine would involve gradually tapering the dose over a period of time to minimize the risk of discontinuation syndrome.
- Medical education, training, and experience are necessary to safely and effectively manage the discontinuation of antidepressant medications, including fluoxetine 1.
- The decision to discontinue fluoxetine should be made in consultation with a healthcare provider, taking into account the individual's medical history, current symptoms, and potential risks and benefits of discontinuation.
It is essential to note that the guideline recommends a gradual tapering of the dose when discontinuing SSRIs, and this approach should be individualized based on the patient's response and tolerance 1. Gradual tapering of fluoxetine can help minimize the risk of discontinuation syndrome and ensure a safe and effective transition off the medication.
From the FDA Drug Label
Discontinuation of Treatment with Prozac — During marketing of Prozac and other SSRIs and SNRIs (serotonin and norepinephrine reuptake inhibitors), there have been spontaneous reports of adverse events occurring upon discontinuation of these drugs, particularly when abrupt, including the following: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paresthesias such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, and hypomania. While these events are generally self–limiting, there have been reports of serious discontinuation symptoms. Patients should be monitored for these symptoms when discontinuing treatment with Prozac A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate
The effects of discontinuing fluoxetine (Prozac) may include:
- Dysphoric mood
- Irritability
- Agitation
- Dizziness
- Sensory disturbances (e.g., paresthesias such as electric shock sensations)
- Anxiety
- Confusion
- Headache
- Lethargy
- Emotional lability
- Insomnia
- Hypomania It is recommended to gradually reduce the dose rather than abruptly stopping the medication to minimize the risk of discontinuation symptoms 2.
From the Research
Effects of Discontinuing Fluoxetine (Prozac)
The provided studies do not directly address the effects of discontinuing fluoxetine (Prozac). However, some information can be inferred from the studies:
- The elimination half-life of fluoxetine is several days, which facilitates the maintenance of steady-state plasma concentrations during long-term treatment 3.
- The elimination half-life of norfluoxetine, an active metabolite of fluoxetine, averages 7 days after long-term administration 4.
- There is no direct information on the effects of discontinuing fluoxetine, but the long half-lives of fluoxetine and its metabolite suggest that the drug may remain in the system for some time after discontinuation.
- Some studies mention the discontinuation of fluoxetine due to adverse effects, such as increasing irritability and hypomania-like symptoms 5, but these are not directly related to the effects of discontinuing the drug.
Adverse Effects of Fluoxetine
Some adverse effects of fluoxetine that may be relevant to discontinuation include:
- Nausea, nervousness, and insomnia 3, 4
- Hypomania-like symptoms, irritability, and gastrointestinal upset 5
- Anxiety, anorexia, diarrhea, and headache 4
Dosage and Administration
The recommended dose of fluoxetine is 20 mg per day, given in the morning or early in the day 6. Some studies suggest that starting with a lower dose and gradually increasing to the standard dose may be beneficial for patients who cannot tolerate the full dose 7.