Amitriptyline in Irritable Bowel Syndrome

What is Amitriptyline?

Amitriptyline was manufactured over 50 years ago and was originally used to treat severe depression. It belongs to a class of drugs called tricyclic antidepressants and has a good safety record.

It is also used for treating chronic pain associated with a number of different conditions. These include back pain, facial pain and any disorders that cause nerve root pain.

There is scientific evidence that Amitriptyline can help the symptoms of irritable bowel, particularly when abdominal pain and diarrhoea are the main symptoms. It can also be effective for painful bloating and nausea. However, it is not licensed for this indication. Please see the information leaflet regarding unlicensed medications provided.

It is prescribed in a much lower dose than used for depression. The usual starting dose is 10mg. It is not addictive or dangerous at this dose and can be taken for several years if necessary.

How does it work?

It remains unclear as to how Amitriptyline works in irritable bowel syndrome. It is very complicated and there is ongoing research in this area.

In depression, it increases the levels of the neurotransmitters (substances produced by the brain) noradrenaline and serotonin. Serotonin also influences the muscular action of the bowel wall which contains special receptors which respond directly to messages from the brain. In irritable bowel syndrome, these messages become disordered and exaggerated. Amitriptyline is thought to work by dampening them down and having an overall calming effect on gut function.

What are the possible side effects?

Side effects can occur and include the following:

• drowsiness
• dry mouth
• blurred vision
• constipation
• urinary retention (difficulty passing urine)
• sexual dysfunction.

How to take it?

We recommend that you take Amitriptyline about 12 hours before you plan to get up in the morning to minimise possible drowsiness. For example, if you usually get up at 7am, then take it at 7pm the night before. We also recommend that you do not plan to drive the morning after you first take it. It is vital to give the medication time to work to its full effect.

This can take two to three months and, during this time, many of the side effects can wear off. If it causes no side effects, and does not help your symptoms, the dose can be gradually increased by your doctor. Alternatively, a different medication may be offered by your specialist.

Contact numbers

If you have any questions or are worried about anything, please contact our Gastroenterology Department on 01305 255393.

About this leaflet

Author: Dr Juliette Loehry, Consultant Gastroenterologist
Written: March 2011
Updated and approved: April 2020, March 2025
Review date: March 2028
Edition: 2

If you have feedback regarding the accuracy of the information contained in this leaflet, or if you would like a list of references used to develop this leaflet, please email patientinformation.leaflets@dchft.nhs.uk