What is the recommended dosing for citalopram (Celexa) in adults with depression, considering factors such as age, hepatic impairment, and severity of symptoms?

Citalopram Dosing in Adults with Depression

Standard Adult Dosing (Age <60 Years)

Start citalopram at 20 mg once daily for most adult patients, with a maximum dose of 40 mg/day due to dose-dependent QT interval prolongation risk. 1, 2, 3

• The initial dose of 20 mg once daily can be increased after 1-2 weeks if clinical response is insufficient 1, 2
• The maximum dose is strictly limited to 40 mg/day in adults under 60 years due to FDA warnings about QT prolongation 1, 2, 3
• Full therapeutic response requires 4-8 weeks at therapeutic doses, so do not assume treatment failure before this timeframe 2
• Peak plasma levels occur at approximately 4 hours, with steady state achieved within one week of daily dosing 3

Elderly Patients (Age ≥60 Years)

For patients 60 years and older, start at 10 mg once daily with a maximum dose of 20 mg/day—this is a mandatory reduction, not optional. 1, 2, 3

• Elderly patients show 23-30% increased drug exposure and 30-50% increased half-life compared to younger adults 2, 3
• The reduced maximum dose of 20 mg/day is required due to significantly elevated QT prolongation risk in this population 1, 2, 3
• Elderly patients are at substantially greater risk for hyponatremia (0.5-12% incidence), typically occurring within the first month of treatment 2, 3
• Regular ECG monitoring is recommended when initiating or adjusting doses in elderly patients 1, 2

Hepatic Impairment

Start at 10 mg daily with a maximum of 20 mg/day in patients with hepatic impairment. 1, 2, 3

• Hepatic impairment reduces citalopram clearance by 37% and doubles the half-life 2, 3
• The dose ceiling of 20 mg/day is mandatory due to QT prolongation risk 1, 2, 3

CYP2C19 Poor Metabolizers and Drug Interactions

Reduce maximum dose to 20 mg/day in CYP2C19 poor metabolizers and patients taking CYP2C19 inhibitors (omeprazole, cimetidine). 1, 2, 3

• CYP2C19 poor metabolizers show 68% increased peak levels and 107% increased drug exposure 2, 3
• Concomitant use of CYP2C19 inhibitors significantly reduces citalopram clearance 1, 2, 3
• This dose reduction is mandatory, not discretionary, due to QT prolongation risk 1, 2, 3

Treatment Duration

Continue treatment for at least 4-12 months after remission for first-episode major depression. 1, 2

• For recurrent depression, prolonged maintenance treatment is recommended at the same dose that achieved remission 1, 2, 4
• Maintenance doses of 20-60 mg have proven efficacy in preventing depressive recurrences 4

Discontinuation Protocol

Taper citalopram gradually over a minimum of 10-14 days to prevent withdrawal symptoms—never stop abruptly. 1, 2

• Withdrawal symptoms are more likely with abrupt cessation after prolonged use 2
• Gradual tapering is essential to limit discontinuation symptoms 1, 2

Critical Safety Monitoring

Monitor for QT prolongation, hyponatremia, and suicidality, particularly during treatment initiation and dose adjustments. 1, 2, 3

• QT prolongation is dose-dependent and the primary reason for mandatory dose ceilings 2, 3
• Hyponatremia occurs in 0.5-12% of older adults taking SSRIs, with elderly patients at substantially greater risk 2, 3
• Suicidality risk is slightly increased in adults 18-24 years; monitor within 1-2 months of initiation or dose increase 2
• Common adverse effects include nausea (most common reason for discontinuation), dry mouth, somnolence, insomnia, and increased sweating 1, 5

Common Pitfalls to Avoid

• Never exceed 40 mg/day in adults <60 years or 20 mg/day in adults ≥60 years—this violates FDA boxed warnings regarding QT prolongation 2, 3
• Do not assume treatment failure before 4-6 weeks at therapeutic doses—full antidepressant effect requires this duration 2
• Do not start at standard doses in elderly, hepatically impaired, or CYP2C19 poor metabolizers—these populations require mandatory dose reductions 1, 2, 3
• For anxious or sensitive patients, consider starting at 10 mg/day initially 1