Citalopram (Celexa) Dosage and Treatment Protocol for Depression
The typical dosage range for Citalopram (Celexa) for depression is 20-40 mg once daily, with a starting dose of 20 mg and a maximum recommended dose of 40 mg due to risk of QT prolongation. 1
Initial Dosing and Titration
- Starting dose: 20 mg once daily (morning or evening, with or without food) 1
- Dose titration: Increase to maximum of 40 mg/day at intervals of no less than one week 1
- Maximum dose: 40 mg/day (doses above this are not recommended due to risk of QT prolongation) 1
Special Population Considerations
Dose Adjustments Required:
- Elderly patients (>60 years): Maximum 20 mg/day 1
- Hepatic impairment: Maximum 20 mg/day 1
- CYP2C19 poor metabolizers: Maximum 20 mg/day 1
- Patients taking CYP2C19 inhibitors (e.g., cimetidine): Maximum 20 mg/day 1
- Renal impairment:
- Mild to moderate: No adjustment needed
- Severe: Use with caution 1
Duration of Treatment
- First episode of depression: Continue treatment for 4-12 months after remission 2
- Recurrent depression: May benefit from prolonged treatment 2
- After first episode: 50% probability of recurrence
- After second episode: 70% probability of recurrence
- After third episode: 90% probability of recurrence 2
Efficacy Considerations
- Citalopram is most effective in patients with severe depression compared to those with mild to moderate depression 2
- Doses of 40 mg/day have shown greater efficacy than lower doses in clinical trials 1, 3
- Therapeutic plasma concentration range: 30-130 ng/mL 2
Discontinuation Protocol
- Never discontinue abruptly - gradual tapering is essential to prevent discontinuation symptoms 1
- Recommended approach:
- Decrease dose gradually
- If intolerable symptoms occur during tapering, resume previously prescribed dose
- Continue decreasing at a more gradual rate 1
Monitoring
- Regular follow-up within 2-4 weeks of starting therapy or after dose changes 4
- Monitor for:
- Clinical response
- Side effects (especially QT prolongation at higher doses)
- Emergence of suicidal thoughts (particularly in adolescents and young adults)
Common Side Effects
- Nausea
- Dry mouth
- Somnolence
- Insomnia
- Increased sweating 3
Important Precautions
- QT prolongation risk: Doses above 40 mg/day are not recommended 1
- Drug interactions: Use caution with CYP2C19 inhibitors (e.g., omeprazole) and CYP3A4 inhibitors (e.g., ketoconazole) 1
- Pregnancy: Use caution, especially in third trimester (risk of neonatal complications) 4
- MAOIs: Allow at least 14 days between discontinuing MAOIs and starting citalopram 1
Clinical Pearl
While citalopram is considered one of the preferred SSRIs due to its favorable side effect profile 2, the FDA has placed a firm limit on maximum dosing at 40 mg/day due to dose-dependent QT interval prolongation risk. This distinguishes it from some other SSRIs that can be safely titrated to higher doses.