Citalopram Dosing Recommendations
The recommended starting dose for citalopram is 20 mg once daily, with a maximum dose of 40 mg daily due to risk of QT prolongation. 1, 2
General Dosing Guidelines
- Initial dose: 20 mg once daily
- Dose adjustment: May increase to 40 mg daily after at least 1 week if needed
- Maximum dose: 40 mg daily (standard adult population)
Special Population Considerations
Elderly (>60 years)
- Maximum dose: 20 mg daily 1
- Pharmacokinetic studies show 30-50% increase in AUC and half-life in patients over 60 years
Hepatic Impairment
- Maximum dose: 20 mg daily 1
- Oral clearance reduced by 37% and half-life doubled in patients with hepatic dysfunction
CYP2C19 Poor Metabolizers
- Maximum dose: 20 mg daily 1
- Citalopram steady state concentrations increased by 68% (Cmax) and 107% (AUC)
Patients Taking CYP2C19 Inhibitors
- Maximum dose: 20 mg daily when taking concomitant cimetidine or other CYP2C19 inhibitors 1
Efficacy Considerations
Clinical studies have shown:
- Doses of 40 mg and 60 mg daily demonstrated significantly greater improvement compared to placebo on all efficacy measures 3
- Lower doses (10 mg and 20 mg) also showed improvement relative to placebo, though with smaller effect sizes 4
- After 6 weeks of therapy, even 10 mg daily showed antidepressive effects, but 40 mg had higher effect sizes 4
Safety Considerations
QT Prolongation Risk
- Citalopram may cause QT prolongation associated with Torsade de Pointes, ventricular tachycardia, and sudden death at daily doses exceeding 40 mg 2
- Avoid in patients with congenital long QT syndrome
Common Side Effects
- Nausea, dry mouth, somnolence, insomnia, and increased sweating 3
- Side effects at 20 mg are more pronounced than at 10 mg, which should be considered when evaluating overall benefit 4
Drug Interactions
- Contraindicated with MAOIs due to risk of serotonin syndrome 2
- Use caution when combining with other drugs that prolong QT interval
- Citalopram has less effect on CYP450 isoenzymes compared to other SSRIs, potentially resulting in fewer drug interactions 2
Administration
- Can be administered at any time of day
- May be taken with or without food (absorption not affected by food) 1
- No dosage adjustment needed based on gender 1
Clinical Pearls
- Citalopram is the most selective serotonin reuptake inhibitor (SSRI) 3
- Pharmacokinetics are linear and dose-proportional in the 10-60 mg/day range 1
- Steady-state plasma concentrations are achieved within approximately one week 1
While some older studies used doses up to 60 mg daily, current recommendations limit the maximum dose to 40 mg daily due to QT prolongation risk identified in more recent safety evaluations.