Fluvoxamine Dosing Schedule
Fluvoxamine should be taken twice daily when the total daily dose exceeds 50-100 mg, with the larger dose given at bedtime. 1
Dosing Frequency by Total Daily Dose
Adults
- 50 mg/day: Single dose at bedtime 1
- 100 mg/day or less: Can be given as single daily dose 1
- More than 100 mg/day: Must be divided into two doses, with the larger dose at bedtime 1
- Maximum dose: 300 mg/day 1
Children and Adolescents (Ages 8-17)
- 25-50 mg/day: Single dose at bedtime 1
- More than 50 mg/day: Divide into two doses, with larger dose at bedtime 1
- Maximum for children ≤11 years: 200 mg/day 1
- Maximum for adolescents: 300 mg/day 1
Practical Dosing Guidance
The twice-daily requirement at higher doses relates to fluvoxamine's pharmacokinetic profile. While the elimination half-life is approximately 15.6 hours in young adults 1, splitting doses improves tolerability and maintains more stable plasma concentrations throughout the day 2, 3.
Key considerations:
- Start with 50 mg at bedtime for adults or 25 mg for children 1
- Increase in 50 mg increments (adults) or 25 mg increments (children) every 4-7 days 1
- When exceeding 100 mg total daily dose in adults or 50 mg in children, split into morning and evening doses 1
- The bedtime dose should be the larger portion when doses are unequal 1
Special Populations
Elderly patients: May require twice-daily dosing even at lower doses due to 50% reduced clearance and longer half-life (25.9 hours vs 15.6 hours in younger adults) 1. Consider more conservative dose escalation.
Hepatic impairment: 30% decreased clearance warrants slower titration and potentially twice-daily dosing at lower thresholds 1.
The guideline data consistently shows fluvoxamine at 50 mg twice daily as the standard starting approach for conditions requiring higher doses 2, 4, though single daily dosing is acceptable for lower total doses to improve adherence 5.