Treating gastrointestinal distress caused by IBS

IBS Image - Masterfile

Irritable bowel syndrome (IBS) can be a frustrating condition for patients and doctors alike. Because it causes no physical abnormalities and its symptoms of abdominal pain, diarrhea, and/or constipation are characteristic of many other digestive disorders, your doctor can diagnose IBS only after ruling out other causes. And since the cause of IBS is not well understood, targeted and effective treatments are somewhat lacking.

Unable to attack the root of the problem, doctors typically utilize treatments that aim to relieve the most bothersome symptoms. Some people also turn to alternative treatments, but little research supports their use.

The good news is that IBS is more benign than most other digestive disorders and does not lead to long-term damage of the gastrointestinal tract. Plus, advances have been made in understanding and treating the condition, and in 2009, the American College of Gastroenterology issued new guidelines on diagnosing and managing IBS based on the most current research.

Pinpointing the Problem: Diagnosing IBS

Because IBS is more commonly diagnosed in those under age 50, older adults need to first determine that another disease more common in the elderly isn't causing their symptoms. For example, older individuals should have a colonoscopy or sigmoidoscopy to rule out the possibility of colorectal polyps or cancer and colitis. People under age 50 without serious symptoms, such as anemia (low hemoglobin levels) or weight loss, are no longer advised to undergo such imaging tests.

Regardless of your age, you should have a blood test for celiac disease if your IBS symptoms involve mostly diarrhea or an alternating pattern of diarrhea and constipation. Your doctor also may perform a breath test for lactose intolerance if your symptoms seem to worsen when eating dairy products. Other blood tests, stool analysis, and abdominal ultrasound are not recommended unless you have serious symptoms.

Once you are diagnosed, your treatment must be tailored to the specific kind of IBS you have: diarrhea-predominant, constipation-predominant, or a mix of the two. Your doctor will weigh the benefits and risks of each one to find the treatment that works for you.

The Most Promising IBS Treatments

The following treatments have the highest-quality evidence to support their use.

Lubiprostone (Amitiza). Approved in 2008, studies show that this prescription laxative is more effective than a placebo for improving symptoms in women with constipation-predominant IBS; corresponding studies have not been done in men. The drug, known as a selective C-2 chloride channel activator, initiates chloride secretion into the intestine, which helps promote bowel movements. Common side effects include nausea, diarrhea and headaches.

Tegaserod (Zelnorm). This drug is also approved for women with constipation-predominant IBS. In studies, women who used Zelnorm were up to 20 percent more likely to see symptom improvement than those on a placebo. Zelnorm is a 5-HT4 receptor agonist, which acts on the neurotransmitter serotonin in the gut to improve gastrointestinal motility. But because of serious cardiovascular side effects (heart attacks and strokes in about 0.1 percent of users), Zelnorm was removed from the market in 2007 and is now available only in emergency situations. The most common side effect is diarrhea.

Alosetron (Lotronex). Clinical trials show that Lotronex, a 5-HT3 receptor antagonist, helps relieve symptoms in women with diarrhea-predominant IBS. Studies are also showing a benefit for men. Like Zelnorm, the drug acts on serotonin in the gut but has the opposite effect, decreasing food transit and reducing physical sensations. However, the drug poses a risk of serious side effects, including severe constipation and reduced blood flow to the colon in 0.1 percent of users. Thus, it's available only through a special prescribing program to women with severe diarrhea-predominant IBS when more traditional IBS treatments have failed. Constipation is the most common side effect.

Antidiarrheals. Loperamide (Imodium) is an effective treatment for diarrhea-predominant IBS, reducing stool frequency and improving consistency, according to two studies. Loperamide does not, however, have any effect on abdominal pain or bloating. Side effects are minor and include tiredness, dizziness, and drowsiness.

Antidepressants. Compared with a placebo, selective serotonin reuptake inhibitor (SSRI) antidepressants like fluoxetine (Prozac) improve abdominal pain and other symptoms of constipation-predominant IBS, and low-dose tricyclic antidepressants (TCAs) such as desipramine (Norpramin) reduce pain and symptoms in diarrhea-predominant IBS. SSRIs likely work by increasing food transit speed through the gastrointestinal tract; TCAs appear to slow this process. Nausea, diarrhea, and headaches are common side effects of SSRIs, while TCAs can cause dry mouth, blurred vision, and drowsiness. Both SSRIs and TCAs can also cause sexual function problems in some people.

Psychological therapies. The latest research shows that cognitive behavioral therapy, dynamic psychotherapy, and hypnotherapy can provide some relief from IBS symptoms. Researchers hypothesize that these therapies work by reducing stress, providing a sympathetic ear, and changing how you think about your symptoms. Relaxation therapy, however, has not proven effective. Psychological therapies have no known side effects.

IBS Research

You may be surprised to see that some of the following treatments don't have much evidence to back them up, especially since they are often recommended for IBS.

Fiber. Most doctors advise people with IBS to consume more fiber in food and supplements, but not much high-quality research supports this. Some evidence suggests that psyllium (Metamucil, for example) works moderately well to provide relief from constipation-predominant IBS, but neither corn bran nor wheat bran are effective.

Laxatives. Doctors often suggest also using an over-the-counter laxative like polyethylene glycol (Miralax) for constipation; however, the effectiveness in people with IBS hasn’t been evaluated in clinical trials. And the one small observational study on adolescents with constipation-predominant IBS showed that while laxatives can help relieve constipation, they don't improve abdominal pain.

Antispasmodics. Because abdominal pain may be caused by intestinal muscle spasms, antispasmodic drugs like dicyclomine (Bentyl) may provide temporary relief. Research shows this to be the case, but most of the studies were of poor quality and the long-term effects are unclear. Even less evidence supports using antispasmodic peppermint oil, available as a dietary supplement.

Antibiotics. Use of rifaximin (Xifaxan) for 10 to 14 days relieves IBS symptoms, especially bloating and diarrhea, according to several studies. Neomycin and metronidazole (Flagyl) have also shown some benefit. However, IBS is a chronic disease that requires ongoing treatment and there are risks to long-term use of any antibiotic, so questions still remain about how antibiotics should be taken for IBS.

Probiotics. Also known as "good bacteria," probiotics have shown some effectiveness as a treatment for IBS. However, there is great variability in probiotic types, preparations, and dosages, making it difficult to generalize about their overall effectiveness. Of the types studied, Lactobacillus doesn't appear to relieve symptoms, while Bifidobacterium and certain combinations of probiotics do. The long-term effects of probiotics are not yet known.

Diet modification. Some people with IBS report that certain foods—like dairy products, additives, preservatives, cereals, potatoes, citrus fruits, and drinks containing caffeine or alcohol—exacerbate their symptoms. However, evidence is weak that excluding these foods from the diet offers symptom relief, and more study is needed. In addition, food allergy testing to determine aggravating foods isn't recommended.

Herbal therapies and acupuncture. Although studies show that Chinese herbal therapies may work as a treatment, concerns about variability, purity, and potentially toxic liver effects make recommendations premature. Studies of acupuncture's effect on IBS have not yielded consistent results, and more research is needed.

The Bottom Line: IBS Treatment

You have a number of treatments to choose from—some with more evidence than others—to help relieve IBS symptoms. Which therapies are best for you depends in part on your symptoms and risk of side effects. It may also take some trial and error to find the most effective treatment(s). If you want to try one of the investigational options, talk to your doctor first.

Publication Review By: H. Franklin Herlong, M.D.

Published: 30 Mar 2011

Last Modified: 22 Sep 2015