Doxepin is a low-dose tricyclic antidepressant used for insomnia, particularly when difficulty is with sleep maintenance (staying asleep). At low doses (e.g., 3–6 mg), it works primarily as an antihistamine (H1 blocker), helping promote sleep without strong sedative hangover effects.

It’s generally well tolerated and not habit-forming, making it a good option for longer-term use compared to some other sleep medications. It does not significantly help with falling asleep, so it’s best for patients who wake up frequently during the night. Common side effects can include mild next-day drowsiness, dry mouth, or dizziness, though these are usually minimal at low doses.