Irritable bowel syndrome (IBS) is the failure of the large intestine to operate properly. In patients with IBS, the large intestine appears to be more sensitive and reactive than normal, resulting in a collection of chronic symptoms that commonly occur after eating or when under stress.

The term "syndrome" is used to describe a pattern of symptoms that tend to occur together. The most common symptom of IBS is abdominal pain associated with diarrhea, constipation or both. Other symptoms of IBS include gas, bloating, cramping and indigestion.

Some patients experience diarrhea-predominant IBS or constipation-predominant IBS. However, most alternate between symptoms of diarrhea and constipation. Abdominal pain is often relieved by having a bowel movement.

IBS is one of the most common disorders diagnosed by physicians in the United States. It is estimated that one in five Americans has IBS. It typically begins around age 20 and occurs in women more often than in men.

Examination of patients with IBS will usually reveal no abnormality of the gastrointestinal tract. Thus, a physician may diagnose IBS based on a patient’s symptoms. A medical history and physical examination can identify any other possible causes for the symptoms. Various imaging or lab tests may also be conducted to rule out other possible medical conditions.

No single cause for IBS has been identified, although diet, stress and anxiety appear to play a role in triggering symptoms in patients with the condition. IBS symptoms may also be aggravated by certain medications or during a woman’s menstrual period. 

There is no cure for IBS, so treatment consists of controlling its symptoms. Various medications can be used to prevent or lessen symptoms. Avoiding particular foods that aggravate IBS symptoms is a common treatment strategy. For example, large meals, alcohol, chocolate, dairy products and caffeinated beverages should be avoided since they can cause diarrhea. Carbonated beverages and chewing gum should also be avoided since they can cause gas and bloating. On the other hand, adding adequate amounts of fiber to the diet can help to alleviate the constipation, and certain kinds of fiber can help to alleviate the diarrhea associated with IBS.  

Activities that reduce stress levels may also help prevent IBS symptoms. These include using relaxation techniques, getting regular exercise and adequate sleep, as well as receiving emotional support through the help of a mental health professional, family members and/or friends.

IBS can affect a person’s quality of life. The severity of symptoms can range from mild and inconvenient to severe and debilitating. IBS may affect a person’s physical functioning and ability to participate in daily activities. Most patients with IBS are able to control their symptoms through a combination of diet, stress management and medication.

IBS is not related to inflammatory bowel diseases that damage the digestive tract, such as Crohn’s disease or ulcerative colitis.

It can, however, affect a person’s quality of life. The severity of symptoms can range from mild and inconvenient to severe and debilitating. IBS may affect a person’s physical functioning and ability to participate in daily activities. Most patients with IBS are able to control their symptoms through a combination of diet, stress management or medication.

It is important to note that the manufacturer of the prescription medication tegaserod maleate (Zelnorn), which was indicated for use in women with constipation-predominant IBS, agreed to discontinue marketing the drug in March 2007 due to a high incidence of adverse cardiovascular events. Patients currently taking this medication are urged to consult their physician. However, select individuals who do not respond to any other form of treatment may be able to continue taking the medication under a restricted access program.

Irritable bowel syndrome (IBS) is considered a functional disorder because it involves the failure of the large intestine to function as it should. It is not a disease, because no identifiable physical abnormality or intestinal damage can be found in patients with IBS. In addition, no single cause of IBS has been identified. Rather, IBS appears to involve unusual sensitivity and muscle activity in the large intestine. This affects the movement of stool and gas through the intestines, causing a variety of symptoms to occur. Stress, emotions and diet can trigger symptoms in patients with IBS.

The term "syndrome" is used to describe a pattern of symptoms that tend to occur together. IBS symptoms include abdominal pain, cramping, bloating, gas, diarrhea and constipation. Abdominal pain that occurs with diarrhea, constipation or both is the most common symptom of IBS. The pain occurs in episodes (not continually) and is often relieved with a bowel movement. Patients with IBS may also experience the sensation of incomplete defecation after a bowel movement. IBS is a chronic condition, in which symptoms can recur throughout a person’s life.

During normal digestion, wave-like muscle contractions (peristalsis) within the intestines occur a few times each day, helping to move contents through the digestive tract before being expelled as waste through the anus. Muscles, nerves and hormones work together to create peristalsis, which maintains normal digestion.

For patients with IBS, nerves and muscles in the large intestine are hypersensitive and can suddenly and involuntarily contract (spasm), speeding digestive content through the intestines and causing diarrhea. Intestinal muscles may also temporarily stop contracting, preventing content from moving forward and causing constipation.

Functional problems that appear to be involved in IBS include:

• Increased sensitivity of the large intestine. In patients with IBS, the large intestine appears to react strongly to stimuli (e.g., anxiety, stress, certain foods) that do not bother most people. For patients with IBS, intestinal nerves may perceive the normal sensations of gas or movement of stool through the digestive tract as excessive and painful.
  
  
• Rapid or delayed transit of stool. In patients with IBS, stool may travel too quickly or in too large an amount for fluid to be properly absorbed by the intestines. Too much liquid in stool causes diarrhea. Or, slowed movement of stool can lead to too much fluid being absorbed, causing constipation.
  
  
• Abnormal muscle contractions. Intestinal muscles may spasm or temporarily stop contracting. Patients with IBS may experience strong contractions that can cause cramping and push stool through the digestive tract too quickly, leading to diarrhea. Spasms may trap gas or stool in one area, leaving it unable to move forward, which can cause cramping, constipation and abdominal pain. This may not occur in all patients with IBS. It is unclear whether this is a cause or symptom of IBS.

The immune system may also be involved. In some rare cases, IBS may develop after severe gastrointestinal infections such as salmonella or campylobacter pylori.

IBS is a very common disorder. According to the National Institutes of Health (NIH), one in five Americans has the disorder, making it one of the most common disorders diagnosed by physicians. IBS affects more than 58 million people in the United States, according to the American College of Gastroenterology (ACG). It occurs more frequently in women than in men, and typically begins around age 20. Many people with IBS do not seek medical attention.

IBS does not permanently harm the large intestine, cause cancer or intestinal bleeding, or lead to other serious diseases. It is not related to inflammatory bowel diseases such as Crohn's disease and ulcerative colitis (both of which cause inflammation and ulcers within the digestive tract). Very few patients with IBS are later diagnosed with some other gastrointestinal condition. In addition, patients with IBS tend to live as long as those in the general population.

However, IBS can alter a person’s lifestyle and impair quality of life. Patients with IBS may experience mild to severe forms of the condition. When mild, IBS symptoms can be annoying and inconvenient. When severe, the symptoms of IBS can be debilitating, preventing people from working, traveling or enjoy social events.

Patients with irritable bowel syndrome (IBS) may experience some symptoms more than others. For example, some patients with IBS mainly experience diarrhea, whereas others primarily experience constipation. Approximately half of all patients with IBS alternate between the two.

Types of IBS are identified by the patient’s predominant symptom and include:

• Diarrhea-predominant (D-IBS). Characterized by abrupt episodes of diarrhea upon waking, or during or immediately after eating. The sudden urgency to have a bowel movement may lead to unintentional soiling. Additional symptoms may include abdominal pain and bloating. Approximately 30 percent of patients with IBS are diarrhea-predominant, according to the International Foundation for Functional Gastrointestinal Disorders (IFFGD).
  
  
• Constipation-predominant (C-IBS). Occurs when periodic constipation, and pain in the lower abdomen are the primary symptoms. Abdominal pain may be sporadic or experienced as a continuous ache, and may be relieved by having a bowel movement. Stool often contains mucus that is white or clear. Eating often triggers symptoms. Occasionally, other parts of the gastrointestinal tract may be affected in addition to or instead of the colon. Indigestion (involving bloating, gas, nausea and heartburn) may also occur. According to the IFFGD, approximately 20 percent of patients with IBS are constipation-predominant.
  
  
• Alternating type (A-IBS). Alternating episodes of both diarrhea and constipation. This is the most common type of IBS.

The cause of irritable bowel syndrome (IBS) is unknown. There is no apparent disease of the bowel involved. Rather, IBS is related to highly stimulated or reactive nerves and muscles in the large intestine.

Stress, anxiety, food intolerances and allergies may all play a role in triggering the symptoms of IBS. In some cases, severe gastrointestinal infections may be associated with the development of IBS even after the infection resolved.

The following are associated with triggering symptoms in patients with IBS:

• Large meals. Digesting large amounts of food at one time can be difficult for patients with IBS. Too much food passing through the digestive tract at once can lead to nutrient and fluid absorption problems, triggering IBS symptoms.
  
  
• Gas. When the intestines are distended due to trapped gas, this can cause abdominal pain and cramping in patients with IBS. Activities such as chewing gum or eating meals quickly can lead to the inadvertent swallowing of air and cause gas.
  
  
• Certain beverages. Foods high in fat (e.g., French fries, potato chips), foods containing artificial sweeteners (e.g., sorbitol), dairy products and chocolate may cause diarrhea, aggravating symptoms in patients with IBS.
  
  
• Specific drinks. Alcohol and drinks that contain caffeine (e.g., coffee, tea, soda) can stimulate digestion, causing or aggravating diarrhea in patients with IBS. Carbonated beverages can cause gas, further worsening IBS symptoms.
  
  
• Emotional stress. Many nerves inside the intestines connect them to the brain. These nerves control functioning and can react adversely to stress. Intestinal muscles may contract too much or too little, leading to chronic diarrhea or constipation. In patients with IBS, the large intestine appears to be extra-sensitive to emotional stress – even slight conflict can cause an adverse response in the intestines, triggering IBS symptoms.
  
  
• Medications. Some medications can negatively affect the digestive system (e.g., cause diarrhea or constipation) and may aggravate symptoms in patients with IBS.
  
  
• Menstruation. Women with IBS may experience more severe symptoms during their menstrual periods.
  
  
• Nicotine. Smoking may aggravate symptoms in patients with IBS.

Factors that may increase a person’s risk of developing IBS include:

• Gender. Although it is not clear why, many more women are diagnosed with IBS than men in Western nations. In the United States, 80 percent of patients with IBS are women, according to the American College of Gastroenterology (ACG). This gender difference may be a cultural phenomenon, however, because in other areas of the world (e.g., India) it is just the opposite – more men than women are diagnosed with IBS.
  
  
• Age. IBS can occur at any age. However, young people are at greater risk of developing IBS. It typically begins in the late teens or early 20s. IBS rarely begins in late adult life.
  
  
• Traumatic life events. Some studies have shown that IBS is more common in people with a history of physical, verbal or sexual abuse.

Irritable bowel syndrome (IBS) can cause a variety of symptoms. They commonly occur after eating or when under stress. Symptoms may vary among patients and can range from mild to severe in intensity. Symptoms of IBS include:

• Abdominal pain. Abdominal pain or cramping associated with bowel functioning is the most common symptom of IBS. Stress and eating may worsen the pain, which usually occurs in the lower left-hand side of the abdomen. Patients with IBS may experience episodes of dull aches or cramps that can range from mild to severe. The pain is often alleviated with a bowel movement. For women, pain may occur or intensify during their menstrual cycle.
  
  
• Diarrhea. Loose, watery stool. Bowel movements most often occur after eating or upon awakening. Diarrhea is usually preceded by a sense of urgency and may be followed by a sensation of incomplete defecation. Soiling may occur as a result of diarrhea.
  
  
• Constipation. Difficulty or straining during a bowel movement, usually involving hard, pellet-shaped stool. Constipation may last days to months in patients with IBS. It is occasionally accompanied by a feeling of incomplete defecation, even when the rectum is empty. Chronic constipation in patients with IBS may lead to straining and the misuse of laxatives or enemas. Patients with IBS may have an urge to defecate, but are unable to do so. Mucus may appear in the stool.
  
  
• Bloating. Gas buildup in the intestines, which can create a sense of increasing pressure in the abdomen. Patients with IBS may experience a swollen or distended abdomen as a result of bloating, as well as an early feeling of fullness when eating. Gas can stretch the bowel and cause cramping or abdominal pain in patients with IBS. Belching may also occur.
  
  
• Other digestive problems. Other gastrointestinal symptoms that can be experienced by patients with IBS include indigestion (including heartburn and nausea) and difficulty swallowing. However, these symptoms may be a symptom of another gastrointestinal problem and not attributed to IBS unless other problems are excluded.
  
  
• Problems outside the digestive tract. Symptoms outside the digestive tract may also appear in patients with IBS. These include fatigue, headaches, back pain, fibromyalgia (a syndrome causing chronic pain), frequent urination, painful menstruation and sexual problems (e.g., painful intercourse or lowered sexual drive).

Symptoms almost always occur while a person is awake. It is rare for symptoms such as diarrhea or abdominal pain to wake patients with IBS from sleep.

Symptoms of IBS are sometimes confused with celiac disease, malabsorption problems and inflammatory bowel diseases (e.g., Crohn's disease and ulcerative colitis). The following are not symptoms of IBS and may indicate other medical problems:

• Bleeding
• Fever
• Unexplained weight loss
• Persistent, severe pain
• Nocturnal diarrhea (diarrhea that awakens a person)

A physician may be able to diagnose irritable bowel syndrome (IBS) based on a medical history and a physical examination. A medical history can include questions about the duration and severity of symptoms, changes in bowel functioning and the relation of symptoms to bowel functioning. Diet, current medications, activity and stress levels may also be discussed. A physical exam can identify signs of other illness that may be causing the symptoms.

Patients may be diagnosed with IBS when they have experienced abdominal pain or discomfort for at least 12 weeks (not necessarily consecutive) in the past year. In addition, patients must meet at least two of the following criteria for a diagnosis of IBS:

• Pain is relieved with the passage of stool
  
• Change in frequency of bowel movements when pain begins
  
• Change in appearance of stool when pain begins

There is no specific diagnostic test used to identify IBS. Instead, tests may be used to rule out other conditions as the cause of a patient’s symptoms. These may include lactose intolerance, infection, diverticulosis, thyroid disorders, inflammatory bowel diseases (e.g., Crohn's disease or ulcerative colitis) or cancer. Tests may be selected based on a patient’s symptoms, the likelihood of other causes of symptoms, as well as the cost and safety of each test.

Tests used to rule out other causes of symptoms in patients with IBS include:

• Blood tests. Drawing of blood from a vein for laboratory analysis. These tests may rule out other conditions that may cause symptoms similar to IBS (such as celiac disease or thyroid disorders).
  
  
• Fecal tests. Laboratory analysis of a stool sample. This may reveal infection or hidden (occult) bleeding, which may indicate various other causes for symptoms.
  
  
• Lactose intolerance tests. Tests that determine whether patients are unable to process lactose (commonly found in dairy products), which may be causing symptoms such as abdominal pain, gas and diarrhea. These tests include a breath test or the systematic elimination of dairy products from the diet under physician supervision.
  
  
• Barium enema x-ray. X-rays taken after a patient has received an enema of a chalky, white substance (barium) that allows internal organs to show up on x-rays. These imaging tests are used to look for any abnormalities that may be causing the symptoms.
  
  
• Endoscopy. An imaging test in which a flexible tube with a camera is inserted into the digestive tract, either through the mouth or the anus. This allows images to be taken of the intestines. Types of endoscopy include colonoscopy (to view the entire large intestine) and sigmoidoscopy (to view the lower portion of the large intestine). These tests may cause spasms and abdominal pain in patients with IBS. They are often recommended as screening tests for colon cancer in patients over the age of 50, but may also be used to rule out conditions that causes similar symptoms to IBS (e.g., inflammatory bowel disease).
  
  
• Anorectal manometry. Balloon catheters are inserted into the anus and rectum and used to test the strength and function of the anal sphincter muscles and exclude anorectal incontinence.
  
  
• Other radiological exams. A computed axial tomography (CAT) scan or an abdominal ultrasound may be used to produce images of internal organs in the abdomen and pelvic areas. These tests allow a physician to look for any abnormalities in these areas.

If no other medical disorder is found to be the cause of a patient’s symptoms, a physician may diagnose IBS based on the patient’s symptoms.

Because there is no cure for irritable bowel syndrome (IBS), treatment consists of controlling its symptoms. For most patients with IBS, this can be accomplished through diet, stress management and/or various medications.

The first step is to identify which foods or activities appear to trigger or aggravate the symptoms of IBS. Symptoms may differ significantly among patients with IBS. It may be helpful to keep a food diary or log of what is eaten each day, the type of symptoms experienced and when they occur and which foods or situations appear to make symptoms worse.

Treatment of IBS symptoms typically involves staying away from foods or behaviors that aggravate symptoms. Some foods may be better tolerated than others. For example, a patient may find that milk aggravates IBS symptoms but that yogurt does not. With the help of a physician, the systematic elimination of certain foods from the diet can also help identify which foods may be related to IBS symptoms.

Specific food and drinks that may worsen IBS symptoms include:

• Fatty foods (French fries, potato chips)
• Dairy products (milk, cheese, ice cream)
• Chocolate
• Caffeinated beverages (coffee, tea, soda)
• Alcohol
• Artificial sweeteners
• Carbonated beverages
• Chewing gum

Patients are at risk of losing key nutrients when they remove certain foods from their diet. A registered dietitian can help with the development of a personalized and healthy food plan.

Patients with IBS may wish to make the following changes to their diet to help alleviate symptoms:

• Consume adequate amounts of fiber. Fiber adds bulk to stool in the digestive tract, speeding digestion and helping to alleviate constipation. In addition, fiber keeps the colon mildly distended, which may help prevent muscle contractions (spasms) in patients with IBS. It may also improve the consistency of stool, helping to alleviate diarrhea. However, too much insoluble fiber may aggravate or cause diarrhea. A patient’s diet should contain enough fiber for easy, painless bowel movements. Fiber should be introduced into the diet gradually to avoid gas and bloating. Fiber supplements may be helpful because it can be difficult to obtain adequate quantities of fiber through diet alone. There are two types of fiber:
  
  
• • Soluble fiber. Fiber that dissolves in liquid, attracts water during digestion and slows the rate of nutrient absorption in the intestines. Thus, soluble fiber may help both diarrhea and constipation associated with IBS. Examples include psyllium, oat bran, oatmeal, barley, rye, fruit flesh (without the skin) and navy, pinto or lima beans.
    
    
  • Insoluble fiber. Fiber that does not dissolve in liquid, speeding digestion and helping to alleviate constipation. Insoluble fiber may worsen diarrhea. Examples include fresh fruit (with the skin), vegetables, whole-grain breads and cereals.
    
    
  It is important to note that most fiber-rich foods contain both soluble and insoluble fiber, but in varying amounts. It is therefore important for IBS patients making dietary changes to learn which foods are most likely to benefit them.

• Eat smaller meals. Eating large amounts of food in a single sitting should be avoided because it may cause cramping and diarrhea. Five or six smaller meals throughout the day may be easier to digest for patients with IBS.
  
  
• Eat slowly. Eating meals too quickly can lead to the unintentional swallowing of air, causing gas and bloating in patients with IBS.
  
  
• Drink plenty of fluids. Six to eight glasses of water a day is recommended for hydration, especially for patients with diarrhea-predominant IBS. 

Patients with IBS may be more sensitive to emotional stress or tension. Stress management is especially important to reduce or prevent the symptoms of IBS. The methods can include:

• Relaxation therapies. Therapies designed to help a person relax. Biofeedback trains patients to alter bodily functions (such as breathing, heart rate and blood pressure) through relaxation or imagery. Progressive relaxation involves a conscious effort to relax muscles in the body, one by one. Meditation, hypnosis, deep breathing and massage may also help a patient with IBS learn to relax so as not to trigger or aggravate IBS symptoms.
  
  
• Counseling. Emotional support usually achieved through communication. This can be done with a mental health professional, in a support group, or with family members or friends. If seeking professional help, cognitive behavior therapy may be especially helpful for patients with IBS.

Patients with IBS should also make an effort to exercise regularly, avoid stressful situations and refrain from smoking, as nicotine may trigger symptoms.

A variety of medications are available to treat the symptoms of IBS. Patients should consult their physician before using any drug (including over-the-counter medications) because it may interfere with current medications or may include serious side effects. Some medications may not be effective for all patients with IBS. As a general rule, medication is used if IBS symptoms do not respond to dietary changes and/or stress management. Medications are most often used for moderate to severe IBS symptoms.

Medications used to treat the symptoms of IBS include:

• Antispasmodics. Drugs that slow or stop intestinal muscle spasms, relieving abdominal pain and cramping and helping to prevent diarrhea.
  
  
• Antidepressants. Low-dose antidepressants act as pain relievers in patients with IBS. One type of antidepressant (tricyclic) also slows the digestive process, which may be helpful for patients with diarrhea-predominant IBS.
  
  
• Tranquilizers. Sometimes used to help patients with IBS avoid emotional distress that may trigger or aggravate symptoms. Tranquilizers are recommended for short-term use only, because they can be habit-forming and may interfere with other medications.
  
  
• Antidiarrheals. Used to treat diarrhea. Some types of antidiarrheals may be more helpful than others for patients with IBS. Ongoing, continual use of these medications is usually not recommended.
  
  
• Fiber supplements/laxatives. Used to treat constipation in patients with IBS. Laxatives should be used with caution, since overuse may cause laxative dependence, constipation and may decrease blood flow to the large intestine.
  
  
• IBS-specific drugs. Designed to affect serotonin receptors in the brain, which in turn affect muscle contractions in the intestines. Drugs known as 5-HT3 antagonists (alosetron hydrochloride) are sometimes prescribed for women with severe diarrhea-predominant IBS. Side effects may include constipation and decreased blood flow to the large intestine. They have not been approved for use by men and are generally used only when other medical therapy for IBS has failed.
  
  Other drugs known as 5-HT4 antagonists (tegaserod maleate, brand name Zelnorn) were prescribed for women with constipation-predominant IBS. However, the manufacturer agreed to discontinue marketing this medication in March 2007 due to a high incidence of adverse cardiovascular events. However, select individuals who do not respond to any other form of treatment may be able to continue taking the medication under a restricted access program. 

Non-traditional remedies have also been used by some people to treat symptoms of IBS. These medications include:

• Oil of peppermint
• Acidophilus (bacteria found naturally in the intestines) supplements
• Chamomile tea
• Evening primrose oil
• Fennel seeds
• Wormwood
• Comfrey

The benefits of these remedies are unproven and in some cases may cause serious side effects or may interfere with other medications. Peppermint oil, for example, is a natural antispasmodic that can help prevent flatulence and cramping. However, it may cause or worsen heartburn. Wormwood may damage the nervous system and comfrey may cause serious liver problems. It is important that patients consult their physician before using any of these alternative therapies.

Acupuncture may provide relief from chronic pain for some patients. Studies on the effectiveness of acupuncture for patients with IBS have been mixed, although some patients have used acupuncture to relax muscle spasms in the intestines and improve digestion.

Surgery does not cure IBS. Patients should obtain a second opinion before considering any type of surgery. Studies have shown that patients with IBS sometimes undergo the unnecessary removal of gallbladders and appendixes, as well as hysterectomies and back surgery with no permanent relief of their IBS symptoms.

Irritable bowel syndrome (IBS) can seriously affect a patient’s quality of life. Living with the recurring symptoms of IBS may mean restricting activity levels and increased levels of emotional distress.

In addition, patients with IBS may be reluctant to talk about or seek help for their symptoms. Chronic diarrhea (which may cause soiling), gas, bloating and constipation can be embarrassing for anyone experiencing these symptoms. Patients with IBS may also experience anxiety and depression as a result of their symptoms.

However, people can learn to cope with the symptoms of IBS and minimize its disruption in their lives. These coping techniques include:

• Identify triggers. Understanding which foods, activities or situations trigger symptoms can help patients reduce or prevent symptoms, minimizing the disruption symptoms can cause. For example, jogging may induce diarrhea in patients with diarrhea-predominant IBS. These patients may want to try other types of exercise such as walking.
  
  
• Learn about IBS. Knowing as much as possible about the condition may help eliminate fear and help patients to more knowledgeably deal with their symptoms.
  
  
• Get emotional support. Developing relationships with others where it is possible to talk openly about IBS and its symptoms can provide emotional release and reduce stress for patients with IBS. Talking with others who also have IBS (e.g., in support groups, Internet chat rooms) can help patients realize they are not alone.
  
  
• Be prepared. Patients with IBS can take actions to lessen the awkwardness or embarrassment of IBS symptoms, especially when traveling or socializing. For example, knowing where restrooms are located or choosing seating that is close to the restrooms can save time and help prevent soiling in cases of sudden or urgent diarrhea. Identifying menu choices ahead of time may allow patients to eat before an event if the only foods available may aggravate their symptoms.

Patients with IBS may wish to experiment with various habits or lifestyle choices that can lessen the severity of their symptoms. For example, wearing loose clothing while eating may reduce the discomfort of bloating in some patients with IBS. Placing warm heating pads on the abdomen after meals may decrease intestinal spasms in some patients with IBS, helping to reduce abdominal pain.

Research continues in the area of treating irritable bowel syndrome (IBS). The role of neurotransmitters (which carry messages from the brain to the rest of the body) in intestinal motility and communicating pain signals is one area of research.

In addition, new medications are being tested for the treatment of symptoms in patients with IBS. These include:

• Cilansetron (a selective 5-HT3 antagonist) is being tested for effectiveness in treating men and women with diarrhea-predominant IBS.
  
  
• Kappa-opioid agonist (fedotozine) is a laboratory-produced narcotic pain reliever designed to reduce abdominal pain.
  
  
• Alpha-2-adrenergic agents are designed to relieve pain and maintain normal bowel functioning.

In addition, the manufacturer of the medication lubiprostone (used to treat chronic idiopathic constipation) is currently seeking market approval from the U.S. Food and Drug Administration of a reduced dosage to treat patients with constipation-predominant IBS.

Specific types of imaging tests are being used in this research. These include brain imaging techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), a type of MRI. These imaging tests may identify areas of the brain which are activated following intestinal stimulation and aid in the development of new medications to help control symptoms of IBS.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to irritable bowel syndrome (IBS):

1. Do my symptoms indicate that I have IBS? Could they be a sign of some other medical condition?
   
   
2. What sort of tests will I need to have to determine if I have IBS?
   
   
3. Do you have experience treating IBS? Do I need to see a specialist?
   
   
4. Could my symptoms be caused by any medications I’m currently taking?
   
   
5. What treatment options are available to me?
   
   
6. Do I need to treat my symptoms when they occur – or will treatment be ongoing, even when I don’t have symptoms?
   
   
7. Do I need to change my diet? What about changes to my lifestyle (exercise, activities)?
   
   
8. If stress aggravates my symptoms, are there particular ways to manage my stress that you recommend?
   
   
9. Are there specific medications that may control my symptoms? Which are most appropriate for me? What are their side effects?
   
   
10. Are there over-the-counter medications or home remedies you would recommend for me?
    
    
11. Are there special things I can do during my menstrual period to lessen or eliminate flare-ups?
    
    
12. During treatment, are there any side effects or changes that you want me to report to you immediately?
    
    
13. I take Zelnorm for IBS with constipation, but heard that it was recently removed from the market. What are my options?