Fluoxetine (Prozac) Dosing for Teenagers
Start fluoxetine at 10 mg/day for one week, then increase to 20 mg/day, which is the effective maintenance dose for most adolescents. 1
Initial Dosing Strategy
- Begin with 10 or 20 mg/day in adolescents, with the FDA label specifically recommending that after 1 week at 10 mg/day, the dose should be increased to 20 mg/day 1
- Lower weight children should start at 10 mg/day due to higher plasma levels in this population, and the target dose may remain at 10 mg/day 1
- Higher weight adolescents can be initiated at 10 mg/day and increased to 20 mg/day after one week 1
Maintenance Dosing
- 20 mg/day is the effective maintenance dose for most adolescents according to the American Academy of Pediatrics 2
- Dose increases to 20 mg/day may be considered after several weeks if insufficient clinical improvement is observed in patients started at 10 mg/day 1
- The maximum dose should not exceed 80 mg/day, though doses above 20 mg/day should only be considered after adequate trial at lower doses 1
Critical Safety Monitoring
- Close monitoring is essential during the first few months of treatment and when changing doses, as recommended by the American Academy of Pediatrics 2
- Monitor specifically for behavioral activation, agitation, and suicidal ideation, particularly during initiation and dose adjustments 2
- Starting at higher doses increases the risk of deliberate self-harm and/or suicide, making the gradual titration approach critical 2
Timeline for Response
- The full therapeutic effect may be delayed until 4 weeks of treatment or longer 1
- Most adverse effects emerge within the first few weeks and are dose-related 3
- Common early adverse events (nausea, insomnia, nervousness, somnolence) typically resolve and become significantly less frequent with continued treatment over 6 months 3
Key Advantages in Adolescents
- Fluoxetine is the only SSRI approved by the FDA for use in children and adolescents with depression 2
- The long half-life of fluoxetine and its active metabolite norfluoxetine essentially preclude withdrawal phenomena 4
- When discontinuation is necessary, fluoxetine should still be slowly tapered to limit withdrawal symptoms 2
Important Contraindications
- Avoid concurrent use with MAOIs - at least 14 days should elapse between discontinuation of an MAOI and initiation of fluoxetine, and at least 5 weeks should be allowed after stopping fluoxetine before starting an MAOI 1
- Monitor for potential drug interactions, as fluoxetine inhibits cytochrome P450 2D6 and can affect metabolism of other medications 2, 4