Amitriptyline
An older antidepressant now mostly used in low doses for nerve pain, migraine prevention and irritable bowel syndrome (IBS). Dangerous in overdose.
Brand names
- Endep, plus generic brands sold as amitriptyline
How it works
It raises serotonin and noradrenaline in the brain and spinal cord, turning down pain signals. Blocking histamine and acetylcholine causes drowsiness and dry mouth. Pain doses (often 5 to 50 mg at night) are much lower than depression doses.
Used for
- Depression (TGA-approved, but now rarely used for this because of side effects and overdose risk)
- Bed-wetting in children, after other causes are excluded (TGA-approved)
- Nerve pain, e.g. shingles pain or diabetic nerve pain (off-label)
- Migraine and tension headache prevention (off-label)
- IBS: low doses improved symptoms in the 2023 ATLANTIS trial in UK general practice (off-label)
Side effects
How often, from the official product information. Bold = serious.
Very common more than 1 in 10
- Drowsiness, dizziness, headache, tremor
- Dry mouth, constipation, nausea
- Blurred near vision, blocked nose
- Fast heartbeat, dizzy on standing
- Sweating, weight gain
- Slurred speech, aggression
Common 1 in 10 to 1 in 100
- Confusion, agitation, low sodium
- Poor focus, odd taste, pins and needles
- Unsteadiness, large pupils
- Heart block, long QT on ECG
- Trouble passing urine
- Low sex drive, erection problems
- Tiredness, thirst
Uncommon 1 in 100 to 1 in 1,000
- Anxiety, poor sleep, nightmares, mania
- Seizures, collapse, worse heart failure
- High blood pressure, ringing ears
- Diarrhoea, vomiting, liver problems
- Rash, hives, flushing, face swelling
- Unable to pass urine, raised eye pressure
Rare 1 in 1,000 to 1 in 10,000
- Low white cells or platelets
- Delirium (older people), hallucinations
- Suicidal thoughts, irregular heart rhythm
- Bowel paralysis, jaundice
- Hair loss, sun sensitivity, fever
- Breast swelling in men
Very rare fewer than 1 in 10,000
- Restlessness (akathisia), nerve damage
- Acute glaucoma (painful red eye)
- Heart muscle disease, torsades
- Lung inflammation
Frequency not known reported, rate unclear
- Anaphylaxis or angioedema
- Severe skin reaction (DRESS)
- Paranoia, movement problems, dry eyes
- Hepatitis, overheating
Get help urgently if
- Overdose is life-threatening, even a few days’ supply. Call 000, or Poisons Information 13 11 26
- Fainting, chest pain or a racing, irregular heartbeat
- A painful red eye with blurred vision
- Unable to pass urine, or severe constipation with tummy swelling
- Thoughts of self-harm: Lifeline 13 11 14
Good to know
- Older people: drowsiness, dizziness on standing and confusion raise the risk of falls. Low doses are used.
- Take 1 to 2 hours before bed. Pain benefit can take 2 to 6 weeks.
- Avoid alcohol and other sedating medicines. Don’t drive until you know how it affects you.
- Many medicines interact, incl. other antidepressants and tramadol. Check with your pharmacist.
- Don’t stop suddenly after long use. Reduce slowly to avoid nausea, headache and poor sleep.
- Pregnancy or breastfeeding: talk to your doctor. Store out of reach of children.
Information only. Not a recommendation or endorsement of any product. Whether a medicine suits you depends on your health and other medicines, so talk to your doctor or pharmacist. In an emergency, call 000.
More information
- Amitriptyline 10 mg SmPC (UK, Brown & Burk)
- NIHR: Low-dose amitriptyline for IBS (ATLANTIS)
- NPS MedicineWise: Medicine Finder
maladywise.com/medicines/amitriptyline/