Antispasmodics are agents used to help reduce one of the more vexing symptoms of IBS -- abdominal pain. It is thought that this pain comes from spasms in the smooth muscle of the intestinal system. Antispasmodics aim to relax and improve the functioning of these muscles, therefore providing relief from symptoms.
In general, studies have shown that antispasmodics are moderately effective in providing short-term relief of IBS pain. There is not a lot of research as to the long-term effectiveness of antispasmodics.
The positive effect of antispasmodics may be particularly beneficial to individuals whose abdominal pain symptoms are worsened when they have just eaten. Because of this, antispasmodics are usually best taken as needed 30 to 60 minutes prior to meals.
The most common antispasmodics are anticholinergic medications and peppermint oil.
Anticholinergic Medications
Prescription antispasmodics are typically of a class of medications called anticholinergics. Anticholinergics act upon the neurotransmitter acetylcholine. Reducing the effect of acetylcholine in the intestines results in a decrease in muscle spasms and a reduction in the secretion of mucus. Unfortunately, this anticholinergic effect also affects other systems within the body, thus resulting in unpleasant side effects:
- Blurred vision
- Constipation
- Decreased urination
- Dizziness
- Dry mouth
Due to the risk of constipation, antispasmodics may be better for the treatment of diarrhea-predominant IBS (IBS-D), rather than constipation-predominant IBS (IBS-C).
The most commonly prescribed antispasmodics in the U.S. are:
- Dicyclomine (Bentyl)
- Hyoscyamine, hyoscamine (Anaspaz, Cystospaz, Levbid, Levsin)
- Hyoscine Butylbromide (Buscopan)
Peppermint Oil
Peppermint is an over-the-counter supplement. The menthol in peppermint oil is thought to have a relaxing effect on smooth muscle, thus reducing gut spasms. There is moderate research support regarding peppermint oil's effectiveness in easing IBS symptoms.
For some, peppermint oil may result in heartburn -- this may be reduced through the use of enteric coated capsules.
Be sure to consult your physician before taking peppermint oil or any other over-the-counter supplements.
Sources:
American College of Gastroenterology IBS Task Force. An Evidence-Based Position Statement on the Management of Irritable Bowel Syndrome. American Journal of Gastroenterology 2009:S1-S35.
Ford, et.al. “Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta-analysis.” BMJ 2008 337:a2313.
Lacy, B., Weiser, K. & Lee, R. The treatment of irritable bowel syndrome. Therapeutic Advances in Gastroenterology 2009 2:221 - 238.
