Medications for Irritable Bowel Syndrome

Antispasmodics

Common names include:

• Hyoscyamine]]> (Anaspaz, A-Spas S/L, Cystospaz, Donnamar, ED-SPAZ, Gastrosed, Levbid, Levsin, Levsinex Timecaps, Levsin/SL, Symax SL)
• Alverine citrate (Spasmonal)
• Tincture of belladonna
• ]]>Dicyclomine]]> (Bentyl)

These medicines may quiet the digestive system and of relieve painful bowel spasms. When taken in reasonable doses, side effects are generally mild.

Possible side effects include:

• Dry mouth
• Nausea
• Dizziness
• Vomiting
• Changes in heart rate
• Palpitations
• Urinary retention
• Visual problems
• Sexual problems
• Sleepiness
• Confusion
• Itching
• Rash
• Allergic reactions

Antidiarrheals

Common names include:

• Codeine]]>
• ]]>Diphenoxylate]]> with Atropine

These medicines are relatives of morphine but much less addicting.

Possible side effects include:

• Dry mouth (from the atropine)
• Nausea
• Vomiting
• Allergic reactions
• Sleepiness
• Confusion
• Lightheadedness
• Dizziness
• Euphoria
• Drowsiness

Antidepressants

Common names include:

• Nortriptyline]]> (Aventyl, Pamelor)
• ]]>Desipramine]]> (Norpramin)
• ]]>Amitriptyline]]> (Elavil, Endep)
• ]]>Imipramine]]> (Norfranil, Tipramine, Tofranil)
• ]]>Fluoxetine]]> (Prozac, Sarafem)
• ]]>Paroxetine]]> (Paxil)
• ]]>Bupropion]]> (Wellbutrin, Zyban)
• ]]>Venlafaxine]]> (Effexor)

All these agents are used to treat depression, a common symptom in people with IBS. Some of these agents (at the top of the list) also have antispasmodic effects and related side effects.

Possible side effects include:

• Dry mouth
• Nausea
• Dizziness
• Sleep disruption
• Diarrhea (with fluoxetine and paroxetine)
• Drowsiness
• Anxiety
• Impaired sexual function (Paxil, Prozac, Zoloft)

Prokinetic Agents

Common names include:

• Cisapride]]> (Propulsid)
• ]]>Domperidone]]> (Motilium)
• ]]>Metoclopramide]]> (Reglan)

Cisapride is an agent used to increase bowel motility. It is available on a very limited, medically approved basis in the United States. While probably the only one of this group of medicines that is consistently effective, cisapride currently carries a warning about fatal heart rhythm disturbances primarily when used with certain other medicines. It should probably be used only with careful supervision by expert physicians specializing in treatment of IBS. Possible side effects include:

• Fatal drug interactions
• Headache
• Diarrhea
• Abdominal pain
• Nausea
• Constipation
• Gas

Domperidone is an antinausea medicine (antiemetic) and also increases the movements and contractions of the stomach and bowel.

Possible side effects include:

• Headache
• Flushing
• Sleepiness
• Dry mouth
• Breast swelling in males

Metoclopromide stimulates motility of the upper GI tract. Side effects include:

• Restlessness
• Anxiety
• Drowsiness
• Fatigue
• Depression
• Insomnia
• Headache
• Dizziness
• Increased risk of ]]>tardive dyskinesia]]> (a serious neurological condition) if taken more than 3 months

Serotonin Agents

Common names include:

• Alosetron]]> (Lotronex)
• Tegaserod (Zelnorm)

Alosetron was re-approved by the FDA in June 2002 for women with severe IBS, unresponsive to other therapy, whose primary symptom is diarrhea. Alosetron can treat diarrhea, as well as general IBS symptoms, including abdominal pain.

The drug acts to block serotonin in the gastrointesinal tract and should be used with caution as it can cause severe side effects. Doctors can prescribe this drug under a risk management plan that requires special informed consent. Possible side effects include:

• Severe constipation
• Decreased blood flow to the colon , possibly leading to serious or fatal complications.

Tegaserod was approved by the FDA in July 2002 for short-term (about four weeks) use in women with IBS whose primary symptom is constipation. The drug acts to activate serotonin receptors in the gastrointestinal tract, thus increasing the movement of stools through the bowels. A possible side effect is diarrhea. However, in March 2007, the FDA withdrew tegaserod from the market due to a slightly increased risk of heart attack, angina, and stroke in patients taking the medicine.

Another medicine called cilansetron has not been approved yet by the FDA. Cilansetron is for men and women whose main IBS symptom is diarrhea. The medicine can treat diarrhea and general symptoms of IBS.

Anxiolytics

Common names include:

• Diazepam]]> (Valium)
• ]]>Chlordiazepoxide]]> (Librium)
• ]]>Clorazepate]]> (Tranxene)
• ]]>Alprazolam]]> (Xanax)
• ]]>Lorazepam]]> (Ativan)
• ]]>Oxazepam]]> (Serax)

Used as a mild sedative for the emotional upset associated with IBS, these agents can be habit-forming. Possible side effects include:

• Drowsiness
• Confusion
• Impaired memory
• Heart rate changes
• Sleepiness
• Constipation/diarrhea
• Rashes
• Dry mouth

Antibiotics

• Rifaximin]]>

While the benefits of rifaximin in IBS remain incompletely established, some data suggests that IBS may not infrequently be caused by “overgrowth” of normal bacteria within the bowel. As a result, medicines that can kill these bacteria (without promoting the growth of disease-causing organisms) have been tried as treatment for IBS. Several studies suggest that rifaximin (a medicine that is not absorbed into the system but remains within the bowel) can reduce at least the symptoms of bloating. There seem to be few if any serious side effects, and some physicians also use this drug when diarrhea is a major symptoms of IBS.

Miscellaneous Medications

• Lubiprostone]]>

Lubiprostone is one of a number of newer medicines that may be effective in IBS. Lubiprostone affects the transfer of chloride across the bowel wall and may be useful in managing IBS when constipation is the primary symptoms and fiber is unsuccessful. Lubiprostone may be safer than alternative medicines, but it is too early to fully judge its effectiveness and safety.

Fiber Supplements

Common brand names:

• Psyllium (Alramucil, Effer-syllium, Fiberall, Konsyl, Metamucil, Modane Bulk, Mylanta Natural Fiber Supplement, Pro-Lax, Reguloid, Serutan, V-Lax)
• Bran
• Polycarbophil (Equalactin, Fibercon, Fiber-Lax, FiberNorm, Mitrolan)
• Methylcellulose (Citrucel)

Dietary fiber is the undigestible part of plants considered important in the optimal functioning of the digestive tract. Initially, fiber supplements may cause bloating and flatulence (gas), which usually subsides within a few weeks. Increase your fiber intake gradually. Drink plenty of water as you increase your fiber to promote regularity. Bran may be less effective than psyllium or other “soluble” fibers.

Possible side effects include:

• Bloating
• Flatulence

Antidiarrheals

Common names include:

• Loperamide
• Lotomil
• Bismuth subsalicylate (Pepto-Bismol)

Loperamide can cause constipation. Bismuth subsalicylate soothes the digestive tract without producing constipation.

Antiflatulents

• Simethicone]]> (Flatulex, Gas Relief, Gas-X, Genasyme, Mylanta, Phazyme, Mylicon Drops)

This agent breaks up bubbles in the stomach to make it easier for gas to exit upward, before it gets into the intestines.

Probiotics

Probiotics]]> are "friendly" bacteria like acidophilus, which is found in yogurt. Probiotics may help improve abdominal pain and other symptoms of IBS. This bacteria can also be bought as supplements. Talk to your doctor if you are interested in adding probiotics to your diet.

Analgesics

• Acetaminophen]]> (Tylenol, etc.)

Findings from a recent clinical trial showed modest benefit of acetaminophen for treatment of crampy abdominal pain in 2000 patients with IBS.