Recommended Starting Dose and Treatment Duration for SSRIs
The recommended starting dose for SSRIs in adults is typically 20 mg daily for fluoxetine, 10 mg daily for paroxetine, 25-50 mg daily for sertraline, and 10 mg daily for citalopram, with treatment duration of at least 4-6 weeks to assess initial response and 6-12 months for maintenance therapy. 1, 2
Starting Doses
Adult Dosing
- Fluoxetine: Start with 20 mg once daily in the morning; lower doses (10 mg daily) may be appropriate for some patients with sensitivity or panic disorder 2, 3
- Paroxetine: Start with 10 mg daily, can be taken morning or evening 1
- Sertraline: Start with 25-50 mg daily, can be taken morning or evening 1
- Citalopram: Start with 10 mg daily 1
- Fluvoxamine: Start with 50 mg twice daily 1
Pediatric Dosing
- For children and adolescents with anxiety disorders, a conservative approach is recommended with lower starting doses 1
- Fluoxetine: Start with 10 mg daily, especially in lower-weight children; may increase to 20 mg after one week if tolerated 2
- A "test dose" approach may be advisable since initial adverse effects can include anxiety or agitation 1
Titration Schedule
- Most SSRIs require gradual dose titration to minimize side effects and optimize efficacy 1
- For shorter half-life SSRIs (sertraline, citalopram): Increase dose at 1-2 week intervals as tolerated 1
- For longer half-life SSRIs (fluoxetine): Increase dose at 3-4 week intervals as needed 1
- Dose increases should be made based on clinical response and tolerability 2
Treatment Duration
Acute Phase
- Initial response assessment: 4-6 weeks is typically required to evaluate efficacy 2
- Full therapeutic effect may not be seen until 4 weeks or longer of treatment 2
- The best-fitting model for SSRI response shows clinically significant improvement by week 6 and maximal improvement by week 12 or later 1
Maintenance Phase
- For major depressive disorder: Maintenance treatment for at least 6-12 months after remission is generally recommended 2
- For anxiety disorders: Long-term treatment is often necessary as anxiety disorders are chronic conditions 1
- Systematic evaluation has shown that efficacy in major depressive disorder is maintained for periods up to 38 weeks following 12 weeks of acute treatment 2
Maximum Recommended Doses
- Fluoxetine: 80 mg/day (though 20 mg/day is sufficient in most cases) 2
- Paroxetine: 40 mg/day 1
- Sertraline: 200 mg/day 1
- Citalopram: 40 mg/day (due to risk of QT prolongation at higher doses) 1
- Fluvoxamine: 150 mg twice daily 1
Special Considerations
Elderly Patients
- Lower starting doses and slower titration are recommended 1
- Consider age-related changes in pharmacokinetics and increased sensitivity to side effects 1
Discontinuation
- Gradual tapering rather than abrupt cessation is recommended to minimize discontinuation symptoms 2
- Discontinuation syndrome is more common with shorter-acting SSRIs (particularly paroxetine, but also fluvoxamine and sertraline) 1
- Symptoms may include dizziness, fatigue, headaches, nausea, sensory disturbances, anxiety, and irritability 1
Common Pitfalls and Caveats
- Inadequate trial duration: Many clinicians discontinue treatment too early before full therapeutic effect is achieved (4-6 weeks minimum) 2
- Insufficient dosing: Starting at appropriate doses and titrating as needed is essential for optimal outcomes 2, 4
- Abrupt discontinuation: Always taper SSRIs gradually to minimize discontinuation symptoms 1, 2
- Drug interactions: SSRIs may interact with other medications through CYP450 enzyme inhibition; citalopram/escitalopram may have the least effect on these enzymes 1
- Monitoring requirements: Close monitoring is recommended, especially in the first months of treatment and following dosage adjustments, due to potential for suicidal ideation (particularly in patients under 24 years) 1
- Behavioral activation/agitation: This can occur early in treatment and may require slower titration or lower doses 1
By following these dosing guidelines and being aware of potential pitfalls, clinicians can optimize SSRI therapy for patients requiring treatment for depression, anxiety, and other indicated conditions.