Celexa (Citalopram) Dosing
For adults with depression or anxiety disorders, start citalopram at 20 mg once daily in the morning, which is the standard initial and therapeutic dose for most patients, with a maximum of 40 mg/day in adults under 60 years old. 1
Standard Adult Dosing (Under 60 Years)
- Initial dose: 20 mg once daily 1
- Maintenance dose: 20 mg/day is sufficient for most patients 1
- Maximum dose: 40 mg/day (doses of 40 mg/day showed efficacy in clinical trials, but 60 mg/day was not more effective than 40 mg/day) 1
- Dose increases should occur only after a minimum of 1 week at the current dose 1
Elderly Patients (≥60 Years)
- Maximum dose: 20 mg/day due to 23-30% increased AUC and 30-50% prolonged half-life compared to younger patients 1
- This lower maximum is mandated because of QT prolongation risk in this population 1
- Elderly patients are at significantly greater risk of adverse drug reactions, particularly hyponatremia 1
Special Dosing Considerations
Patients Taking CYP2C19 Inhibitors
- Maximum dose: 20 mg/day when taking concomitant cimetidine or other potent CYP2C19 inhibitors (e.g., omeprazole) due to QT prolongation risk 1
- CYP3A4 and CYP2C19 are the primary metabolic enzymes for citalopram 1
Hepatic or Renal Impairment
- Use lower or less frequent dosing, approximately 50% of standard adult starting dose 2
Clinical Efficacy Evidence
- Depression: Fixed doses of 40 and 60 mg/day demonstrated efficacy in 6-week trials, though 10 and 20 mg/day showed no clear effect in one study 1
- Relapse prevention: Patients continuing citalopram 20-40 mg/day showed significantly lower relapse rates over 6 months compared to placebo 1
- Anxiety disorders: While not FDA-approved for anxiety, research supports effectiveness at mean doses of 33 mg/day (range 10-60 mg/day) for generalized anxiety disorder 3
Administration Guidelines
- Timing: Take once daily, preferably in the morning (SSRIs can be activating) 2
- With or without food: Can be taken either way 1
- Titration: Allow at least 1 week between dose increases to assess response 1
Common Pitfalls to Avoid
- Do not exceed 40 mg/day in adults under 60 or 20 mg/day in elderly patients—higher doses increase QT prolongation risk without additional efficacy 1
- Do not use 60 mg/day—clinical trials showed this dose was not more effective than 40 mg/day 1
- Monitor elderly patients closely for hyponatremia, as SSRIs carry increased risk in this population 1
- Be aware that citalopram is a weak inhibitor of CYP2D6, though clinically significant interactions are unlikely 1