Doxepin

1 medicine

Doxepin is a tricyclic antidepressant used at low doses for insomnia and itching and at higher doses for depression, but overdose is dangerous because it can cause life-threatening heart rhythm problems, and it must never be combined with an MAOI.

Sinequan

Doxepin

10/25/75mg

Sinequan is a antidepressants medication containing Doxepin, available as 10/25/75mg tablets.

from $0.47 / tablet View

Key facts

  • Doxepin is a tricyclic antidepressant (TCA). At low doses it is used mainly for insomnia and itching; at higher doses it treats depression.
  • Low-dose tablets for sleep are taken shortly before bedtime; higher antidepressant doses are usually taken once daily and adjusted gradually.
  • Doxepin overdose is dangerous: even a moderate excess can cause life-threatening heart rhythm disturbances, seizures, and severe drowsiness. It must never be combined with an MAOI or taken within 14 days of stopping one, since the combination can cause a severe, potentially fatal reaction.
  • Seek urgent care for a fast or irregular heartbeat, fainting, confusion, or a seizure.

What doxepin treats

At very low doses, doxepin treats insomnia, difficulty staying asleep, and chronic itching from skin conditions. At higher doses, it treats depression. It is sometimes used for chronic pain conditions such as nerve pain, though this use is less common than with newer medicines.

How doxepin works

Doxepin increases the amount of two brain chemicals, serotonin and noradrenaline, that regulate mood and alertness, by slowing how quickly nerve cells reabsorb them. At low doses, its strong blocking effect on histamine receptors is what produces sleepiness and eases itching; at higher doses, its effect on mood-regulating chemicals becomes more relevant.

Before you take it

  • Do not take doxepin if you have taken an MAOI antidepressant in the last 14 days, or if you have untreated narrow-angle glaucoma, severe urinary retention, or a recent heart attack.
  • Tell your prescriber about any heart rhythm problems, seizures, liver disease, or an enlarged prostate.
  • Alcohol and other sedating medicines add to drowsiness and increase the risk of dangerously slowed breathing.
  • Combining doxepin with other serotonin-raising medicines, including some migraine drugs and other antidepressants, can cause serotonin syndrome.

Side effects

Common effects include drowsiness, dry mouth, constipation, blurred vision, and mild dizziness on standing.

Stop and seek urgent medical care for any of these:

  • A fast, pounding, or irregular heartbeat.
  • Severe drowsiness, confusion, or difficulty waking.
  • Swelling of the face, lips, tongue, or throat.
  • A seizure, or new agitation and restlessness with sweating or tremor (possible serotonin syndrome).

Safety essentials

  • Doxepin is toxic in overdose: it can cause life-threatening arrhythmias, dangerously low blood pressure, and seizures, and doses need extra care in anyone with existing heart disease.
  • Never combine doxepin with an MAOI; a 14-day gap is required in either direction between the two medicines.
  • Older adults are more sensitive to doxepin's sedating and anticholinergic effects, including confusion, falls, and urinary retention, so lower doses are used when treating insomnia.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.