Irritable bowel syndrome (IBS) is a common condition affecting the large intestine. While IBS does not cause serious damage to the intestines, it can bring about bothersome and sometimes disabling symptoms of abdominal cramping, diarrhea, constipation and bloating. According to the National Digestive Diseases Information Clearinghouse (NDDIC), IBS is usually controllable through diet, stress management and medication. Both over-the-counter and prescription drugs are available to treat the symptoms of IBS.
Over-the-Counter Drugs
For those who suffer from constipation, laxatives or over-the-counter fiber supplements, such as psyllium or methylcellulose, may provide relief, according to the Mayo Clinic. Anti-gas drugs, such as simethicone, and anti-diarrheal medications, such as loperamide, may also help those with diarrhea-predominant IBS.
Alosetron Hydrochloride
Alosetron hydrochloride is a medication approved by the Food and Drug Administration (FDA) for restricted use in the treatment of IBS. According to NDDIC, the drug was once removed from the market in the United States due to serious complications. It has since been re-approved for use only among women with severe cases of diarrhea-predominant IBS who have not responded to other treatments. The drug is not intended for use among men. Because alosetron hydrochloride can cause severe constipation and decreased blood flow to the colon, it is generally prescribed by a gastroenterologist who can closely monitor its side effects.
Lubiprostone
Also approved by the FDA for the treatment of IBS, lubiprostone is intended for women 18 or older who have IBS with severe constipation. According to the Mayo Clinic, lubiprostone increases the secretion of fluid in the small intestine and is believed to ease the passage of stool. Because more research is needed regarding the drug's safety and effectiveness, it is usually only prescribed when other treatments have failed to bring about an improvement in symptoms. As of 2010, lubiprostone has not been proven effective in men.
Antidepressants
Antidepressant drugs may prove helpful for some people with irritable bowel syndrome who also have depressed mood. Antidepressants act on neurotransmitters in the brain to alleviate depression, and they may also inhibit the activity of neurons that control the intestines, according to the Mayo Clinic. A class of antidepressants called selective serotonin reuptake inhibitors (SSRIs) may be appropriate for those who are feeling depressed and have problems with constipation and abdominal pain. SSRIs that might be prescribed include fluoxetine or paroxetine. Individuals with abdominal pain, diarrhea and depression may benefit from a low dose of tricyclic antidepressants, such as imipramine or amitriptyline.
Other Prescription Drugs
Prescription antispasmodic drugs, such as phenobarbital, that relax the muscles in the bladder and digestive tract may be prescribed, according to NDDIC. Anti-cholinergic drugs that relieve muscle spasms by targeting the autonomic nervous system may also be effective for some people. For example, the combination anti-cholinergic and anti-anxiety drugs chlordiazepoxide and clidinium may help improve bowel function.
