Amitriptyline
2 medicines
Amitriptyline is a tricyclic antidepressant used for depression, nerve pain and migraine prevention. It is highly cardiotoxic in overdose, so only small, carefully counted quantities should be kept at home.
Key facts
- Amitriptyline is a tricyclic antidepressant (TCA) used for major depressive disorder, chronic nerve pain, migraine prevention and, at low doses, insomnia.
- You usually take it once daily in the evening, since it causes drowsiness; pain relief can start within days, while mood benefits take 2 to 4 weeks.
- Amitriptyline is dangerous in overdose. Even a modest excess can cause life-threatening heart rhythm disturbances, seizures and coma, so only a limited supply should be kept at home, particularly if anyone in the household is at risk of self-harm.
- In people under 25, amitriptyline can increase suicidal thoughts and behaviour, especially early in treatment. Seek urgent care for fainting, a fast or irregular heartbeat, or confusion.
What amitriptyline treats
Amitriptyline treats major depressive disorder and chronic nerve pain, including diabetic neuropathy and pain after shingles. It is also used to prevent migraine and tension-type headaches, and in low doses to help with insomnia.
How amitriptyline works
Nerve cells release serotonin and norepinephrine, chemical messengers involved in mood and pain signalling, and then reabsorb them. Amitriptyline blocks that reabsorption (reuptake), so more of both stay active between nerve cells. It also blocks several other receptors, which explains its strong sedative and anticholinergic effects (dry mouth, blurred vision, constipation) alongside its mood and pain benefits.
Before you take it
- Never take amitriptyline within 14 days of a monoamine oxidase inhibitor (MAOI); the combination can cause serotonin syndrome, which can be fatal.
- Do not use amitriptyline soon after a heart attack, or if you have a heart rhythm disorder, uncontrolled glaucoma or severe urinary retention; it can worsen all of these.
- Tell your prescriber about any personal or family history of suicidal thoughts, since overdose risk is a central safety concern with this medicine.
- Never stop amitriptyline suddenly. Taper the dose down gradually under medical guidance to avoid nausea, headache and flu-like withdrawal symptoms.
Side effects
Common effects: dry mouth, drowsiness, constipation, blurred vision and weight gain.
Stop and seek urgent medical care for any of these:
- New or worsening suicidal thoughts, especially if you are under 25.
- Fainting, a fast or irregular heartbeat, or chest pain.
- Agitation, high fever, muscle twitching or confusion (serotonin syndrome).
- Severe rash, swelling or difficulty breathing.
- A suspected overdose: this is a medical emergency, even if the person seems well at first.
Safety essentials
- Amitriptyline is highly cardiotoxic in overdose and a leading cause of fatal antidepressant poisoning. Keep only a limited supply at home, store it securely, and treat any suspected overdose as a medical emergency requiring immediate attention.
- This class carries a warning for increased suicidal thinking in people under 25, particularly in the first weeks of treatment.
- Never combine amitriptyline with an MAOI, and taper off slowly rather than stopping abruptly.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.