Switching from Sertraline 150 mg to Fluvoxamine 100 mg
Perform a direct switch by stopping sertraline 150 mg and starting fluvoxamine 100 mg the next day, as both are SSRIs with similar mechanisms and no washout period is required between them. 1
Switching Strategy
Direct Switch Approach
- Stop sertraline 150 mg completely and begin fluvoxamine 100 mg the following day. 1
- This direct switch method is appropriate because both medications are SSRIs with overlapping serotonergic activity, minimizing the risk of discontinuation symptoms or treatment gaps. 1
- No tapering of sertraline is necessary when switching to another SSRI at therapeutic doses. 1
Fluvoxamine Initiation
- Start fluvoxamine at 50 mg daily for the first few days, then increase to 100 mg daily to improve tolerability. 2
- Fluvoxamine can be administered as a single daily dose or divided into twice-daily dosing (50 mg BID). 2
- The FDA label indicates that fluvoxamine should be slowly titrated during initiation, particularly in elderly patients, though you are using a standard adult dose. 2
Monitoring During the Switch
First 2-4 Weeks
- Monitor closely for withdrawal symptoms from sertraline discontinuation, including dizziness, nausea, headache, irritability, and sensory disturbances. 1
- Watch for signs of serotonin syndrome during the overlap period, though risk is low with this switch strategy: agitation, confusion, rapid heart rate, dilated pupils, muscle rigidity, and hyperthermia. 3
- Assess for suicidal thinking and behavior, especially in the first weeks after the medication change. 3
Efficacy Assessment
- Allow 6-8 weeks at the target dose of fluvoxamine 100 mg before assessing full therapeutic response. 2
- If inadequate response after 6-8 weeks, fluvoxamine can be increased in 50 mg increments up to a maximum of 300 mg daily in adults. 2
Important Caveats
Avoid Gradual Taper Unless Necessary
- Conservative switching strategies involving gradual tapering and washout periods are unnecessarily prolonged for SSRI-to-SSRI switches and risk treatment gaps with potential depressive exacerbations. 1
- Gradual tapering is only indicated if the patient has a history of severe discontinuation symptoms or if switching to a medication with different mechanisms (e.g., MAOIs). 1
Drug Interactions
- Never combine with MAOIs - ensure no MAOI use within 14 days before starting fluvoxamine. 3
- Be aware that fluvoxamine has significant cytochrome P450 interactions that sertraline does not have to the same degree, potentially affecting other medications the patient takes. 2