What is the recommended dose of citalopram (Celexa) for an adult patient with depression, considering factors such as age, hepatic impairment, and medical history?

Citalopram Dosing for Adult Depression

Standard Adult Dosing (Age <60 Years)

For most adult patients with depression, start citalopram at 20 mg once daily, which can be increased to a maximum of 40 mg/day if needed after 1-2 weeks of insufficient response. 1, 2, 3

• The FDA label confirms that the typical dosage range is 20-40 mg per day for adult outpatients, with doses of 40 mg/day showing particularly robust antidepressant effects 3, 4
• Clinical trials demonstrated that 40 mg/day and 60 mg/day were significantly more effective than placebo, while 10 mg/day and 20 mg/day showed more modest benefits 4
• However, the maximum dose should not exceed 40 mg/day due to dose-dependent QT interval prolongation risk 2, 3
• Steady-state plasma concentrations are achieved within approximately one week of once-daily dosing 3

Critical Dose Reductions for Special Populations

Elderly Patients (Age ≥60 Years)

The maximum dose is 20 mg/day for patients 60 years and older, with no option for dose escalation. 2, 3

• Citalopram AUC increases by 23-30% and half-life increases by 30-50% in elderly patients compared to younger adults 3
• This mandatory dose reduction is required due to increased risk of QT prolongation in this age group 3
• Starting doses should be approximately 50% of standard adult doses (consider starting at 10 mg/day) 1

Hepatic Impairment

The maximum dose is 20 mg/day for patients with hepatic impairment. 3

• Citalopram oral clearance is reduced by 37% and half-life is doubled in hepatically impaired patients 3
• This dose reduction is mandatory due to QT prolongation risk 3
• Consider starting at 10 mg/day in patients with significant hepatic dysfunction 1

CYP2C19 Poor Metabolizers

The maximum dose is 20 mg/day for CYP2C19 poor metabolizers. 3

• These patients have 68% higher Cmax and 107% higher AUC at steady state 3
• The dose reduction is required due to QT prolongation risk from elevated drug levels 3

Patients Taking CYP2C19 Inhibitors

The maximum dose is 20 mg/day when citalopram is combined with CYP2C19 inhibitors such as omeprazole or cimetidine. 2, 3

• CYP2C19 is one of the primary enzymes involved in citalopram metabolism 3
• Potent inhibitors significantly reduce citalopram clearance, necessitating dose reduction to prevent QT prolongation 2, 3

Renal Impairment

No dose adjustment is required for mild to moderate renal impairment. 3

• Oral clearance is reduced by only 17% in mild-moderate renal impairment 3
• No data exists for severe renal impairment (creatinine clearance <20 mL/min), so use caution in this population 3

Treatment Duration

Continue treatment for at least 4-12 months after remission for a first depressive episode. 2

• Patients with recurrent depression may benefit from prolonged maintenance treatment 2
• Long-term studies demonstrate that continuing citalopram at the acute treatment dose (20-60 mg) effectively prevents depressive recurrences 5
• When discontinuing, taper gradually over 10-14 days minimum to limit withdrawal symptoms 1

Dose Titration Strategy

If increasing the dose, wait at least 1-2 weeks before escalating, as full therapeutic response requires 4-8 weeks. 1, 2

• Dose increases should use increments of the initial dose every 5-7 days until therapeutic benefits or significant side effects appear 1
• The 60 mg/day dose studied in trials was not more effective than 40 mg/day and is not recommended due to QT prolongation risk 3, 4

Common Pitfalls to Avoid

• Never exceed 40 mg/day in standard adults or 20 mg/day in elderly patients, hepatically impaired patients, CYP2C19 poor metabolizers, or those on CYP2C19 inhibitors 2, 3
• Do not assume gender requires dose adjustment—no clinically significant differences exist between men and women 3
• Monitor for hyponatremia, particularly in elderly patients who are at greater risk 3
• The most common side effects leading to discontinuation are nausea and vomiting, which typically occur early in treatment 1, 4