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Prescription Drugs For IBS

Anticholinergics, Antidepressants, and Anti-diarrheals Are Often Prescribed

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Updated October 01, 2013

What Medications Are Used To Treat IBS?

Several different types of drugs may be used to treat IBS. The goal of medication is to lessen troublesome IBS symptoms such as diarrhea, cramping, pain, or constipation.

Anticholinergics. This class of drugs affects the nerve cells or nerve fibers and are used to calm muscle spasms in the intestine and help symptoms of IBS such as cramping pain or diarrhea. Some of the drugs used to treat IBS are actually combinations of two drugs: an anticholinergic and a mild sedative.


  • Dicyclomine (Bentyl). Dicyclomine relaxes the muscles of the gut and bladder to prevent spasms, and reduces the amount of stomach acid produced. Dicyclomine can be safely used long-term, under the guidance of a physician. Common side effects include constipation, dryness of mouth, nose, throat, or skin and a decreased ability to perspire (which can contribute to heat stroke).

  • Belladonna/Phenobarbital (Donnatal, Antispas, Barbidonna, Donnapine, Hyosophen, Spasmolin). This combination of two drugs is used to relax the muscles in the bladder and intestines as well as reduce stomach acid. Phenobarbital is a mild sedative can be habit-forming. Common side effects of belladonna/phenobarbital include headache, nausea, constipation, rash, and vomiting. This drug may take 4 or 5 days to be effective, and, under the supervision of a physician can be safely used long-term.

  • Hyoscyamine (Levsin, Anaspaz). This combination of two drugs, belladonna alkaloids and barbiturates, is used to relax the muscles in the bladder and intestines as well as reduce stomach acid. Common side effects include headache, nausea, constipation, rash, and vomiting. Hyoscyamine may be taken long-term under the guidance of a physician as long as side effects are absent or tolerable.

  • Chlordiazepoxide/clidinium (Librax). Chlordiazepoxide/clidinium prevents spams in the gut and also the bladder. Chlordiazepoxide is a sedative, and may be habit forming. Common side effects include bloated feeling, decreased sweating, dizziness, drowsiness, dryness of mouth, and headache. This drug may take 4 or 5 days to be effective, and, under the supervision of a physician can be safely used long-term.

Anti-diarrheals. Anti-diarrheals are used to slow down the effect of the bowel. These drugs may used to prevent diarrhea that occurs from IBS.

  • Diphenoxylate/atropine (Lomotil). The diphenoxylate portion of this drug is used to treat diarrhea, while the atropine relieves muscle spams in the gut. Common side effects include headache, dizziness, drowsiness, blurred vision, dry mouth, and constipation. Although it is not a narcotic, diphenoxylate is derived from narcotics and may be mildly habit-forming. Diphenoxylate/atropine is typically prescribed to control diarrhea in the short-term, and is not recommended for long-term use.

New agents.

  • Alosetron hydrochloride (Lotronex). This newer drug is only used to treat women with severe D-IBS. Alosetron hydrochloride was approved and then pulled from the market by the Food and Drug Administration after several cases of serious side effects in women taking it. It is now only approved for use on a limited basis, and should not be used for C-IBS or A-IBS. Alosetron hydrochloride disrupts the action of seratonin, a chemical in the body that has an affect on intestinal movement and pain. Treatment usually begins with a 4-week trial and may be continued for another 4 weeks under the supervision of a physician.

  • Tegaserod (Zelnorm, Zelmac). Tegaserod is used for treating C-IBS in women and works by helping move stool through the intestine. Tegaserod has the same effect on the body as serotonin, a chemical that the body produces naturally. Therapy with tegaserod is normally given for 4 to 6 weeks, but may be extended for up to 12 weeks. Common side effects include headache, abdominal pain, diarrhea, nausea, and gas. Tegaserod is a new drug, therefore, information about long-term effects are not available.

Amber J. Tresca
About.com Inflammatory Bowel Disease (IBD)

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