Doxepin Indications
Doxepin is FDA-approved for two distinct clinical indications: (1) treatment of depression and/or anxiety in adults, and (2) treatment of sleep maintenance insomnia at ultra-low doses (3 mg and 6 mg) in adults. 1
FDA-Approved Indications
1. Psychiatric Indications (Higher Doses: 25-300 mg/day)
Doxepin is approved for treating the following conditions 1:
- Psychoneurotic patients with depression and/or anxiety
- Depression and/or anxiety associated with alcoholism (not to be taken concomitantly with alcohol)
- Depression and/or anxiety associated with organic disease (consider drug interactions if patient receives other medications concomitantly)
- Psychotic depressive disorders with associated anxiety, including:
- Involutional depression
- Manic-depressive disorders
Target symptoms that respond particularly well include anxiety, tension, depression, somatic symptoms and concerns, sleep disturbances, guilt, lack of energy, fear, apprehension, and worry 1.
2. Insomnia (Ultra-Low Doses: 3 mg and 6 mg)
Doxepin at 3 mg and 6 mg is specifically indicated for sleep maintenance insomnia in adults 2. The American Academy of Sleep Medicine (AASM) 2017 guidelines provide a WEAK recommendation for using doxepin as treatment for sleep maintenance insomnia versus no treatment 2.
Key Evidence for Insomnia Indication:
- Clinically significant improvements in wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE) 2
- Minimal improvement in sleep latency (does not significantly affect sleep onset) 2
- Benefits sustained into the last third of the night without next-day residual effects 3
- Low-strength evidence due to potential publication bias and imprecision, but benefits outweigh harms 2
Important Dosing Distinctions
The indication depends critically on the dose:
- 3-6 mg doses: Sleep maintenance insomnia only
- 25-300 mg doses: Depression and anxiety disorders
- Not approved for children under 12 years of age 1
Contraindications
Doxepin is contraindicated in 1:
- Patients with hypersensitivity to the drug
- Patients with glaucoma or tendency to urinary retention
- Concomitant use with MAO inhibitors
Critical Safety Considerations
Black Box Warning
All antidepressants, including doxepin, carry a black box warning for increased risk of suicidal thinking and behavior in children, adolescents, and young adults (ages 18-24) with major depressive disorder and other psychiatric disorders 1. Close monitoring is required, especially during initial treatment phases and dose adjustments.
Geriatric Use
Doxepin is safe and well-tolerated in elderly patients, but sedating drugs may cause confusion and oversedation in the elderly; start with low doses and observe closely 1. The once-daily dosing regimen should be adjusted carefully based on the patient's condition.