Antidepressants are commonly used as a treatment option for people with irritable bowel syndrome with diarrhea (IBS-D). Some antidepressants for IBS have also shown to be effective at low doses in IBS patients with constipation (IBS-C).1,2 Antidepressants, while initially developed to treat depression, have been shown to be effective in treating pain and symptoms from functional GI disorders, like IBS.3
In addition to the disturbances in intestinal motility (resulting in either diarrhea or constipation) and abdominal pain that are experienced by people with IBS, recent studies have also shown that the normal function of the brain being able to “turn down” pain signals sent from the gut is impaired. The pain can become severe when the person is experiencing emotional distress, which may occur due to stresses in life or due to the stress and frustration of IBS symptoms. Antidepressants can help the brain-gut dysfunction of IBS.3
There are different kinds of antidepressants, categorized for how they work in the body. Antidepressants for IBS often include:
- Tricyclic antidepressants
- Selective serotonin reuptake inhibitors
- Serotonin-norepinephrine reuptake inhibitors1,2
Tricyclic antidepressants for IBS treatment
Tricyclic antidepressants (TCAs) work by affecting the naturally occurring chemical messengers, called neurotransmitters, in the brain and body. TCAs block the absorption (or reuptake) of the neurotransmitters serotonin and norepinephrine. In clinical trials, people with IBS-D who took a low-dose TCA experienced a significant reduction in the number of loose stool and the feeling of incomplete bowel movements compared to people who were taking a placebo (a harmless pill that produces no physical effects).
TCAs also have an effect on the neurotransmitter acetylcholine, which is involved in muscle spasms of smooth muscle, like those found in the intestines. Because of this effect, they may cause constipation and are better suited for people with IBS-D. However, they can be effective without significant side effects at lower doses in people with IBS-C.1,3,4
TCAs have been available and on the market for many years and are relatively inexpensive. Some TCAs used in the treatment of IBS include:
- Amitriptyline (Elavil)
- Imipramine (Tofranil)
- Desipramine (Norpramin)
- Nortriptyline (Pamelor)3
People taking TCAs may experience the following side effects: dry mouth, difficulty sleeping at times, difficulty urinating, sexual difficulties, constipation, dizziness and/or drowsiness.3
These are not all the possible side effects of TCAs. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with TCAs.
Selective serotonin reuptake inhibitors for IBS treatment
Selective serotonin reuptake inhibitors (SSRIs) target the neurotransmitter serotonin and have been shown to promote global well being in some people with IBS as well as improve some of the abdominal pain and bowel symptoms. Some SSRIs have proven effective in treating pain in a number of conditions, but the effectiveness of SSRIs on the gut have not been clearly proven in research. The exact ways SSRIs work in IBS are not completely understood by the scientific and medical community.5
SSRIs include:
- Citalopram (Celexa)
- Escitalopram (Lexapro)
- Paroxetine (Paxil)
- Sertraline (Zoloft)
- Fluoxetine (Prozac)
People taking SSRIs may experience side effects, such as nervousness, vivid dreams, sleep disturbances, sexual difficulties, and/or diarrhea.3
These are not all the possible side effects of SSRIs. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with SSRIs.
Serotonin-norepinephrine reuptake inhibitors for IBS treatment
Serotonin-norepinephrine reuptake inhibitors (SNRIs) block the absorption of the neurotransmitters serotonin and norepinephrine and have proven effective in many pain-related disorders. In addition, like other antidepressants, they help with overall mood.3
SNRIs include:
- Venlafaxine (Effexor)
- Duloxetine (Cymbalta)
- Desvenlavaxine (Pristiq)
- Milnacipram (Savella)
Common side effects experienced by people taking SNRIs include nausea, headache, and rarely, changes in liver chemistry tests.3
These are not all the possible side effects of SNRIs. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with SNRIs.
Other treatment options for IBS
People with IBS often have to try several treatment options before finding the right combination of approaches that work best to manage their symptoms. In addition to antidepressants, people can try a variety of lifestyle approaches – including dietary changes, exercise, adding fiber or probiotics, and managing their stress levels – or other medicines such as antispasmodics, antibiotics, antidiarrheals, and laxatives.
Before beginning treatment for IBS, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.
