Antidepressant Drugs for IBS

Reviewed by: HU Medical Review Board | Last reviewed: December 2023

For people with irritable bowel syndrome (IBS), symptoms can be difficult to manage. Recurring symptoms of abdominal pain, bloating, and altered bowel habits interfere with daily life. In addition to diet and lifestyle changes, your doctor may recommend prescription drugs to treat IBS.1

Antidepressant drugs are sometimes used to manage IBS symptoms. These drug types (classes) are not approved by the US Food and Drug Administration to treat IBS. But they are often used off-label for IBS and other painful conditions.2

Using a drug off-label means that the FDA has not approved it to treat that condition. It also means the FDA has not yet determined whether the drug is safe and effective for that purpose.3

IBS and the gut-brain axis

Irritable bowel syndrome is a complex disorder that involves communication between the digestive system (gut) and the nervous system. This interaction is called the gut-brain axis. Research continues to shed light on the complex brain-gut interactions behind IBS.1,2,4

Chemical messengers in the nervous system called norepinephrine, dopamine, and serotonin play a role in the painful abdominal symptoms linked to IBS. Antidepressant drugs affect these chemical messengers. As a result, these drugs influence the gut-brain axis and can help ease IBS symptoms.1,2,4

IBS and mood disorders

People with IBS are at higher risk of having depression and anxiety. Antidepressant drugs can improve mental health, which may help with digestive symptoms. But these drugs also appear to help with IBS symptoms even if you do not have anxiety or depression.2,4

How do antidepressants work for IBS?

Antidepressants have a wide variety of effects on the body, including:1,4

  • Reducing painful sensations
  • Decreasing inflammation and gut sensitivity
  • Changing how fast food moves through the gut
  • Improving depression

What antidepressants are used for IBS?

Numerous studies have shown that certain drugs used to treat depression are effective in treating IBS symptoms.1,2,4

The most common classes of antidepressant drugs used to treat IBS are low-dose tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs).1,2,4

Tricyclic antidepressants (TCAs)

TCAs have been studied extensively for use in IBS and other pain syndromes, including fibromyalgia, headaches, nerve pain, and low back pain. The dose of TCAs used to treat IBS is lower than that used to treat depression.1,2,4

The following TCAs have been studied for the treatment of IBS:2

  • Amitriptyline
  • Desipramine
  • Doxepin
  • Imipramine
  • Trimipramine
  • Nortriptyline
  • Dothiepin

Selective serotonin reuptake inhibitors (SSRIs)

Some experts recommend SSRIs as a treatment option. But fewer studies have looked at the use of SSRIs for IBS. The dose of SSRIs used for IBS is the same as that used to treat mood disorders.2

Studies of the following SSRIs have demonstrated benefit for people with IBS:2

  • Citalopram
  • Fluoxetine
  • Paroxetine

Serotonin and norepinephrine reuptake inhibitors (SNRIs)

SNRIs are a class of antidepressants that are used to treat pain. These drugs have not yet been studied for the treatment of IBS. More research is needed to see if they can help people with IBS.2

The following SNRIs are used to treat pain:2

  • Duloxetine
  • Milnacipran

What is the best antidepressant for IBS?

Which drug your doctor recommends will depend on your specific IBS symptoms and other medical conditions. The best option for you will depend partly on whether you have:2

  • IBS with constipation (IBS-C)
  • IBS with diarrhea (IBS-D)
  • IBS with mixed stool pattern (IBS-M)

TCAs may be a better option for IBS-D because they slow down how quickly food moves through the gut. TCAs also seem to be more effective than SSRIs at relieving abdominal pain.5

In contrast, SSRIs may be a good option for people with IBS-C because they speed up the movement of food through the gut. SSRIs are also a good option if you have IBS and depression. More research is needed to determine who may respond better to a particular drug.2,6

What are the side effects of antidepressants?

TCAs are more likely than SSRIs to cause drowsiness, dry mouth, and constipation. To prevent side effects, experts recommend starting at a low dose. Your doctor will slowly increase the dose until symptoms improve.1

Other side effects of TCAs include:1

  • Difficulty sleeping
  • Irregular heartbeat
  • Decreased appetite
  • Flushing

SSRIs cause less dry mouth, constipation, and drowsiness than TCAs. The most common side effects of SSRIs include:7

  • Changes in sleep
  • Weight changes
  • Anxiety
  • Dizziness
  • Headache
  • Stomach upset

Overall, the evidence is strong that antidepressant drugs are an effective option for many people with IBS. Unfortunately, for some people, IBS symptoms do not improve with a TCA or SSRI. Trying a different drug or dose may help.1,2,4

The best treatment plan for you will depend on your specific symptoms. Medicine is just one part of a treatment plan that will likely include lifestyle changes, nutrition, prescription medicine, and behavioral therapy.1,2,4

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