Doxepin: Uses, Safety and Drug Interactions

Doxepin: uses, safety and drug interactions

Overview: Doxepin has more than one medicinal use and formulation. This page mainly covers the low-dose 3 mg and 6 mg oral tablets licensed in the United States for insomnia. Those tablets are not interchangeable with antidepressant-strength capsules or topical doxepin products.

Uses and formulation: The low-dose tablets are intended for difficulty maintaining sleep, rather than as a general treatment for every cause of poor sleep. Persistent symptoms require assessment for another disorder. Meal timing and the opportunity for adequate sleep matter because unwanted effects can remain into the next day. The prescribed product instructions should be followed without changing the dose or substituting a higher-strength capsule.

Safety: Doxepin must not be used with current or recent monoamine oxidase inhibitor treatment, untreated narrow-angle glaucoma or severe urinary retention. Severe sleep apnoea also needs particular caution. Sleepiness, dizziness, unusual night-time behaviour or worsening depression should be reported. Breathing difficulty, inability to wake or suicidal thoughts require urgent assessment. Breastfeeding is not recommended in the selected US label because serious effects have been reported in exposed infants; pregnancy needs individual review.

Drug interactions: Alcohol, sedating antihistamines and other central nervous system depressants may increase impairment. Medicines that inhibit CYP2D6 or CYP2C19 can increase doxepin exposure. In a small healthy-volunteer study, sertraline increased doxepin exposure and worsened some psychomotor test results; this is not a prediction of the same clinical effect in every patient. A clinician or pharmacist should review the complete list, including other sleep medicines, before treatment changes are made.

Sources

• US prescribing information — doxepin 3 mg/6 mg insomnia tablets
• WHO Collaborating Centre ATC/DDD Index 2026 — N06AA12
• Nexium 40 mg gastro-resistant tablets UK SmPC
• FDA clinical CYP enzyme and transporter interaction examples

This page provides an English summary of the cited sources. Source check: 30 October 2026. This date records a source check, not a clinical review by a doctor or pharmacist. Follow the current leaflet for your product and seek professional advice for personal treatment.