Discontinuing Aripiprazole and Starting Fluoxetine in a Patient Without Psychotic Symptoms
Yes, you can and should discontinue aripiprazole and start fluoxetine in this patient, as aripiprazole is indicated for schizophrenia and schizoaffective disorder—conditions this patient does not have—while fluoxetine is appropriate first-line treatment for depression and anxiety disorders. 1, 2
Rationale for Discontinuation
- Aripiprazole is specifically indicated for schizophrenia, schizoaffective disorder, and as adjunctive treatment for major depressive disorder (MDD), not as monotherapy for depression or anxiety without psychotic features 1, 2
- If this patient has no history of schizophrenia, hallucinations, or psychotic symptoms, there is no evidence-based indication for continuing aripiprazole 1, 2
- The optimal dose of aripiprazole for schizophrenia is 10 mg/day, with doses above 20 mg providing no additional benefit, suggesting its use should be reserved for appropriate indications 3
Discontinuation Protocol for Aripiprazole
- Taper aripiprazole gradually over 1-2 weeks rather than stopping abruptly, as discontinuation syndrome has been reported with sudden cessation 4
- Monitor for withdrawal symptoms including nausea, insomnia, anxiety, and agitation during the taper period 4
- Aripiprazole has a long elimination half-life of approximately 75 hours, which provides natural coverage during tapering 5, 2
Suggested Taper Schedule:
- If on 10-15 mg daily: reduce to 5-7.5 mg for 5-7 days, then discontinue 5, 4
- If on higher doses: reduce by 25-50% every 5-7 days 5
Starting Fluoxetine
- Begin fluoxetine at 10-20 mg daily after completing the aripiprazole taper or during the final days of taper, as there is no contraindication to overlap 6
- Fluoxetine has a long half-life (3-4 weeks with active metabolites), so dose increases should occur at 3-4 week intervals if needed 6
- The therapeutic range for fluoxetine in depression and anxiety is typically 20-60 mg daily 6
Critical Safety Considerations
Drug Interactions to Monitor:
- Both aripiprazole and fluoxetine are metabolized by CYP2D6, so during any overlap period, be aware of potential increased levels of either medication 6, 2
- Avoid combining fluoxetine with MAOIs or other serotonergic agents due to risk of serotonin syndrome 6
- Monitor for QT prolongation if the patient is on other QT-prolonging medications, though fluoxetine has lower risk than citalopram 6, 7
Monitoring Parameters:
- Assess for serotonin syndrome symptoms within 24-48 hours of starting fluoxetine: mental status changes, neuromuscular hyperactivity (tremors, clonus), and autonomic instability 6
- Monitor for suicidal ideation, especially in younger patients, during the first 4-8 weeks of SSRI treatment 6
- Watch for bleeding risk, particularly if patient takes NSAIDs or aspirin concurrently 6
Common Pitfalls to Avoid
- Do not stop aripiprazole abruptly without tapering, as this increases risk of discontinuation syndrome 5, 4
- Do not assume aripiprazole augmentation is appropriate for non-psychotic depression—it is FDA-approved only as adjunctive therapy, not monotherapy, and only after SSRI trials 1, 2
- Do not increase fluoxetine dose before 3-4 weeks, as its long half-life means steady state is not reached for several weeks 6
- Avoid paroxetine or fluvoxamine if considering alternative SSRIs, as these have higher discontinuation syndrome rates and more drug interactions than fluoxetine 6