What is the recommended dosing for doxepin (a tricyclic antidepressant) in adults with depression or anxiety?

Doxepin Dosing for Depression and Anxiety

Standard Dosing for Depression and Anxiety

For most patients with mild to moderate depression or anxiety, start doxepin at 75 mg daily, with a usual therapeutic range of 75-150 mg/day. 1

Initial Dosing Strategy

• Start at 75 mg/day for patients with mild to moderate illness 1
• Dosage may be increased or decreased at appropriate intervals based on individual response 1
• The usual optimum dose range is 75-150 mg/day 1

Dosing for Severe Illness

• More severely ill patients may require higher initial doses 1
• Doses can be gradually increased to 300 mg/day if necessary 1
• Additional therapeutic effect is rarely obtained by exceeding 300 mg/day 1

Dosing for Very Mild Symptoms

• Patients with very mild symptomatology or emotional symptoms accompanying organic disease may require lower doses 1
• Some patients have been controlled on doses as low as 25-50 mg/day 1

Administration Schedule

Total daily dosage may be given on a divided or once-daily schedule. 1

Once-Daily Dosing

• If once-daily schedule is employed, the maximum recommended dose is 150 mg/day 1
• This dose may be given at bedtime 1
• The 150 mg capsule strength is intended for maintenance therapy only and is not recommended for initiation of treatment 1

Special Population Considerations

Elderly Patients

• Start at the low end of the dosing range in elderly patients 1
• Elderly patients should be started on low doses and observed closely due to risk of confusion and oversedation 1
• Greater caution is needed due to higher frequency of decreased hepatic, renal, or cardiac function 1

Timeline for Therapeutic Effect

• Anti-anxiety effect appears before the antidepressant effect 1
• Optimal antidepressant effect may not be evident for 2-3 weeks 1

Low-Dose Doxepin for Insomnia (Off-Label)

Low-dose doxepin at 3-6 mg once daily at bedtime is effective for chronic primary insomnia in adults and elderly patients, but should not be used for insomnia in depressed patients. 2, 3

• Doxepin 3 or 6 mg once daily improved wake time after sleep onset, total sleep time, and sleep efficiency significantly more than placebo in patients with chronic primary insomnia 2
• Efficacy was maintained for up to 12 weeks with no evidence of physical dependence or rebound insomnia after withdrawal 2
• However, low-dose doxepin (<25 mg/day) does not appear to improve sleep onset or maintenance in patients with major depressive disorder 3

Critical Prescribing Caveats

• Doxepin is a tricyclic antidepressant with anticholinergic effects including dry mouth, blurred vision, constipation, and urinary retention 1
• Drowsiness is the most commonly noticed side effect, which tends to disappear as therapy continues 1
• Cardiovascular effects including hypotension, hypertension, and tachycardia have been reported occasionally 1
• Gradual withdrawal is necessary to avoid withdrawal symptoms after prolonged administration 1