What are the withdrawal symptoms of Prozac (fluoxetine)?

Withdrawal Symptoms of Prozac (Fluoxetine)

Prozac (fluoxetine) withdrawal symptoms typically include dysphoric mood, irritability, agitation, dizziness, sensory disturbances (such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, and hypomania. 1

Common Withdrawal Symptoms

• Dizziness and vertigo are among the most frequently reported symptoms when discontinuing Prozac 2
• Sensory disturbances including paresthesias and "electric shock" sensations 1
• Psychological symptoms including anxiety, irritability, confusion, and emotional lability 1
• Sleep disturbances including insomnia and excessive dreaming 3
• Headache, fatigue, and lethargy 2
• Nausea, vomiting, and gastrointestinal disturbances 2
• Flu-like symptoms 3

Timing and Duration of Symptoms

• Withdrawal symptoms typically begin within 24-48 hours after discontinuation of the medication 3
• Symptoms generally reach maximum intensity around day 5 3
• Without intervention, symptoms may persist for 1-2 weeks, though in some cases they can last up to 3 weeks 3, 2
• Prozac has a longer half-life compared to other SSRIs, which may result in less severe or less frequent withdrawal symptoms 4
• If the medication is restarted, symptoms typically resolve within 72 hours 2

Risk Factors for Withdrawal

• Abrupt discontinuation rather than gradual tapering significantly increases risk of withdrawal symptoms 1
• Longer duration of treatment increases the risk of withdrawal symptoms 4
• Higher dosages may lead to more severe withdrawal symptoms 3
• Poor medication compliance (intermittent use) can trigger withdrawal symptoms 3
• Concomitant medication use and alcohol consumption may worsen withdrawal 3

Severe Withdrawal Manifestations

• While rare, delirium has been reported following abrupt discontinuation of fluoxetine 5
• Hypomania may occur during withdrawal 1
• In severe cases, withdrawal symptoms can significantly impair daily functioning 2

Prevention and Management

• A gradual reduction in dose rather than abrupt cessation is strongly recommended 1
• Tapering should ideally occur over a period of more than four weeks 6
• If intolerable withdrawal symptoms occur during dose reduction, resuming the previously prescribed dose may be considered, followed by a more gradual taper 1
• Patients should be monitored for withdrawal symptoms when discontinuing treatment 1
• Patient education about potential withdrawal symptoms is important for prevention and management 3

Clinical Considerations

• Withdrawal symptoms are often mistaken for relapse of the original condition, but withdrawal typically begins within days of discontinuation while true relapse usually takes longer to develop 2
• The long elimination half-life of fluoxetine and its active metabolite (norfluoxetine) means that plasma concentrations decrease gradually at the conclusion of therapy, which may minimize the risk of discontinuation symptoms compared to other SSRIs 1, 4
• Withdrawal symptoms from fluoxetine are generally less severe than those from shorter-acting SSRIs like paroxetine and fluvoxamine 4
• Withdrawal symptoms should not be confused with serotonin syndrome, which is a different condition resulting from excessive serotonergic activity rather than decreased serotonin 7