Discontinuation Effects of Fluoxetine
Fluoxetine has minimal withdrawal symptoms compared to other SSRIs due to its very long half-life, making abrupt discontinuation relatively safe and well-tolerated. 1
Key Characteristics of Fluoxetine Discontinuation
Fluoxetine is uniquely protective against discontinuation syndrome because its active metabolite (norfluoxetine) has an elimination half-life that provides natural tapering over weeks, unlike shorter-acting SSRIs. 1
Minimal Withdrawal Profile
Abrupt discontinuation of fluoxetine produces few clinically significant symptoms in most patients, with only mild, self-limited lightheadedness or dizziness occurring in a small percentage of cases. 1
In controlled studies, patients who abruptly stopped fluoxetine after 12 weeks of treatment showed similar rates of new adverse events compared to those continuing treatment, with no cluster of symptoms suggesting a discontinuation syndrome. 1
Patient discontinuation rates related to adverse events were equivalent between those who stopped fluoxetine and those who continued it. 1
Rare Discontinuation Symptoms
When symptoms do occur, they may include:
- Dizziness or incoordination (most common when symptoms occur). 2
- Headaches. 2
- Nausea. 2
- Irritability. 2
Exceptional Cases
- Delirium has been reported in isolated case reports following abrupt fluoxetine discontinuation, though this is extremely rare and atypical. 3
Comparison to Other SSRIs
Fluoxetine has significantly lower risk of discontinuation syndrome compared to paroxetine, fluvoxamine, sertraline, and venlafaxine, which commonly produce withdrawal symptoms. 4, 2, 5
Paroxetine, venlafaxine, and fluvoxamine produce frequent and sometimes severe discontinuation reactions, including psychological symptoms (anxiety, depression, confusion, irritability) and somatic symptoms (dizziness, nausea, headache). 2, 5
86% of patients abruptly withdrawn from fluvoxamine developed new symptoms, with symptoms peaking at Day 5 post-discontinuation. 2
Clinical Recommendations
Fluoxetine can be stopped abruptly without tapering in most patients due to its pharmacokinetic properties providing natural dose reduction over weeks. 1
For patients switching from fluoxetine to another antidepressant, no washout period is typically needed, though the long half-life means fluoxetine effects persist for weeks. 1
General guideline for discontinuing antidepressants suggests tapering over 10 to 14 days to limit withdrawal symptoms, but this is less critical for fluoxetine specifically. 6
Important Caveats
Fluoxetine may offer a safety advantage for patients likely to miss doses due to travel or forgetfulness, as treatment interruption is better tolerated than with shorter-acting agents. 1
Do not confuse discontinuation symptoms with depression relapse—true discontinuation syndrome symptoms emerge within days and resolve spontaneously, while depression recurrence develops more gradually. 1
The very long half-life that protects against withdrawal also means side effects may persist for weeks after stopping, which can be problematic if switching medications or if side effects were the reason for discontinuation. 6