What is the recommended dosing for fluvoxamine (selective serotonin reuptake inhibitor - SSRI) in adults?

Fluvoxamine Dosing in Adults

Start fluvoxamine at 50 mg once daily at bedtime, then increase by 50 mg increments every 4-7 days as tolerated until reaching the therapeutic range of 100-300 mg/day, with doses above 100 mg split into two divided doses (larger dose at bedtime). 1

Initial Dosing Strategy

• Begin with 50 mg as a single daily dose at bedtime in adults 1
• This starting dose allows assessment of tolerability before escalation 1
• Morning dosing may be considered if sedation is problematic, though bedtime administration is standard 1

Titration Protocol

• Increase the dose by 50 mg increments every 4-7 days based on tolerability 1
• The therapeutic dose range established in clinical trials is 100-300 mg/day 2, 1
• Maximum daily dose should not exceed 300 mg 1
• When total daily dose exceeds 100 mg, split into two divided doses with the larger dose given at bedtime 1

Expected Timeline for Response

• Statistically significant improvement may occur within 2 weeks of treatment 3
• Clinically meaningful response typically emerges by week 6 3
• Maximal therapeutic benefit usually occurs by week 10-12 or later 3
• Clinical trials have demonstrated efficacy with early onset of therapeutic effect starting from week 2 4

Special Population Considerations

Elderly or Hepatically Impaired Patients

• These patients demonstrate decreased clearance of fluvoxamine 1
• Modify both the initial dose and subsequent titration schedule accordingly 1
• Consider starting at lower doses and advancing more slowly 1

Critical Safety Monitoring

Suicidality Monitoring

• Monitor patients closely for suicidality, particularly those ≤24 years old, during the first months of treatment and after all dose adjustments 3

Serotonin Syndrome Risk

• Fluvoxamine is contraindicated with MAOIs due to serotonin syndrome risk 3
• Watch for signs of serotonin syndrome throughout treatment 3

Drug Interaction Considerations

• Fluvoxamine is a potent CYP1A2 inhibitor and moderate inhibitor of CYP2C19 and CYP3A4 2
• Avoid concomitant use with alprazolam or triazolam due to significant interaction risk 2
• Exercise caution when combining with other medications metabolized by these pathways 3, 2

Maintenance Treatment

• Continue treatment for responding patients, as OCD is a chronic condition requiring extended therapy 1
• Adjust dosage to maintain patients on the lowest effective dose 1
• Periodically reassess to determine the need for continued treatment 1
• Maintenance therapy may reduce the likelihood of relapses in up to 67% of patients with OCD 5

Discontinuation Protocol

• Taper gradually rather than stopping abruptly to minimize discontinuation syndrome 1
• Fluvoxamine carries a higher risk of discontinuation syndrome compared to some other SSRIs due to its shorter half-life 3, 2
• Discontinuation symptoms include dizziness, fatigue, myalgias, headaches, nausea, insomnia, sensory disturbances, anxiety, and agitation 3
• Monitor patients for these symptoms when discontinuing treatment 1

Common Pitfalls to Avoid

• Do not advance doses too quickly: Rushing titration increases adverse effects without improving efficacy 1
• Do not underdose: The effective therapeutic range is 100-300 mg/day, and doses below 100 mg may be subtherapeutic 2, 1
• Do not forget to split doses: Once exceeding 100 mg daily, divide into two doses to improve tolerability 1
• Do not abruptly discontinue: Always taper gradually to prevent withdrawal symptoms 3, 1