Targeted IBS Medications
There targeted medications that have been shown to be effective in treating IBS in multi-center, high quality clinical trials. These are prescription medications intended for specific use under a doctor’s supervision.
Alosetron (Lotronex) blocks serotonin signals that transmit sensations (painful and non-painful) from the gut to the brain. It helps to reduce diarrhea and belly pain. Alosetron has been approved for the use in women with severe diarrhea-predominant IBS. It is prescribed under a Risk Management Plan designed to reduce the risk of rare but potentially serious side effects.
Lubiprostone (Amitiza) helps to promote secretion through chloride channels in the bowel. These in turn promote the coordinated muscle contractions (peristalsis) that propel content through the GI tract. This medication has been shown to be effective for treating constipation symptoms. It is approved for use in women with constipation-predominant IBS, and in men and women with chronic constipation (without predominant abdominal pain).
Linaclotide (Linzess) is in a class of medications called guanylate cyclase-C agonists. It works by increasing the movement of contents through the GI tract and by blocking pain signals in the intestines. The medication is prescribed in adults aged 18 and older for IBS with constipation and for chronic constipation. In studies, patients taking linaclotide experienced improvement in multiple symptoms including pain or discomfort, bloating, and bowel function.
Newer Medications Being Tested
There is a potential role of some bacteria residing in the gut to be associated with IBS symptoms in some people. Recent studies have shown that antibiotics, which reduce or alter the bacteria in the gut, may relieve some symptoms of IBS.
Rifaximin is one antibiotic, currently under investigation for IBS. In studies it has been found to improve IBS symptoms after a 10–14 day course of treatment. It is only slightly absorbed in the gut and is generally tolerated well. Although some patients may experience relief of IBS symptoms for up to 2–3 months after taking rifaximin, more information is needed about the duration of symptom relief and the best management approach to prevent recurrence of symptoms or if symptoms recur.
Source: Lembo T and Rink R. Current Pharmacologic Treatments of Irritable Bowel Syndrome. IFFGD Fact Sheet No. 168.