One-third of people who have irritable bowel syndrome have significant problems with diarrhea. Diarrhea can describe many different characteristics—too rapid stools or too loose stools, for instance—but most physicians define the condition as more than three bowel movements per day. People who have IBS and the predominant complaint of diarrhea do not all have identical bowel patterns. Some are troubled by frequent loose bowel movements throughout the day, while others have them only after eating a meal. Patients may have 3 to 4 movements per day or be overwhelmed by 12 to 15 per day. Some individuals who have IBS feel that they are able to control their episodes of diarrhea, no matter how frequent; others are frustrated by the significant urgency associated with their diarrhea and fear having an accident.
As discussed in Chapter 6, for people who have IBS and diarrhea, food travels more rapidly through either the small intestine or the colon or both. Despite the accelerated transit through the intestinal tract and despite the frequent bowel movements, most patients have normal stool weights, that is, they do not produce more stool than people who do not have IBS. In addition, and contrary to what one might expect, people who have IBS and diarrhea do not typically become dehydrated, nor do they lose weight or become malnourished from failure to absorb sufficient nutrients.
Because people who have IBS and diarrhea experience more rapid transit of material through their gastrointestinal system, most therapies used to treat them focus on slowing down the GI tract, using either over-the-counter or prescription medications, both discussed below. The initial evaluation of patients who have IBS with diarrhea will include a careful review of the patient’s diet, and there are some dietary adjustments, described below, that may help relieve symptoms. In contrast to patients who have IBS and constipation, for whom changes in fluid intake and exercise may lead to some improvement, these interventions are not effective for people who have IBS and diarrhea.
Unrecognized dietary indiscretions often contribute to the chronic diarrhea that characterizes IBS. If you are a person who has symptoms of IBS, it is important during your initial evaluation to review your diet carefully with your physician, in order to determine whether dietary factors are adversely affecting your bowel habits. This dietary review should include both your main meals and any snacking and on-the-run eating. All liquids that you drink should be noted, along with nutritional supplements, vitamins, natural medications, fiber supplements, and herbal supplements. Keeping a careful food diary for the week prior to your appointment will not only help you give a correct accounting of your daily intake of foods and liquids but also may help identify any foods or liquids that are triggering symptoms.
As discussed in Chapter 10, lactose and fructose are two food elements that have the most potential to worsen symptoms in patients who have IBS and diarrhea, although fibrous foods, fiber supplements, and caffeine are also frequent offenders. Your physician will be interested in your intake of dairy foods, not only milk, but also cheese, ice cream, cottage cheese, and yogurt (recognizing that most lactose is broken down during the fermentation process of making yogurt). He or she might suggest a one-week trial of abstaining from all dairy products as a good way to determine whether milk and other dairy products play a role in your symptoms.
Fructose occurs naturally in many fruits and is used as a sweetener in a variety of foods and liquids, usually in the form of high-fructose corn syrup. Soft drinks, fruit drinks, sports drinks, “energy drinks,” and many nutritional supplements derive a large percentage of their calories from high-fructose corn syrup. Some people routinely drink one or two glasses of juice at breakfast, have two or three soft drinks during the day, and then consume a sports drink after exercising. All of these drinks contain large amounts of fructose, and this amount of fructose can easily overwhelm the absorptive capacity of the GI tract and cause diarrhea, even in healthy people who do not have IBS.
Clinicians have long recognized that patients who have IBS and diarrhea seem to be more sensitive to fructose than other people, but the reason was not known. Research has now shown that up to 50 percent of patients who have IBS and diarrhea may not be able to break down and absorb fructose normally. Unabsorbed fructose acts like an osmotic agent, drawing extra water into the intestinal tract, thereby accelerating intestinal transit. In addition, when unabsorbed fructose enters the colon, it is broken down by bacteria during the process of fermentation. This produces gas (hydrogen and carbon dioxide), which can further worsen symptoms of bloating and distention. The same process occurs with unabsorbed lactose.
Many patients find that completely avoiding all fructose-containing foods for an entire week dramatically improves (but does not eliminate) their symptoms. They can then slowly add back small portions of fructose-containing foods and liquids, to determine how tolerant or intolerant they are to specific products. They may be able to tolerate two cans of soda or one soft drink and one glass of juice with minimal or no symptoms, while an intake of three servings per day produces significant symptoms of gas, bloating, distention, and diarrhea.
Another dietary factor that can worsen symptoms in individuals who have diarrhea is fiber. For years, we’ve all been told that eating a lot of fiber is good for us. In many ways, this is true, as diets high in fiber can aid in weight loss, lower blood pressure, lower cholesterol, and help maintain bowel health in people who do not have diarrhea. However, too much fiber can overwhelm the GI tract and worsen many of the symptoms for a person who has IBS. Specifically, too much fiber can accelerate intestinal transit, leading to diarrhea. In addition, fiber that is not broken down will pass into the colon and, when broken down by bacteria there, produce gas, exacerbating bloating and distention.
People who have IBS and diarrhea are often mistakenly told that adding more fiber to their diet will improve their symptoms. This advice is given in the belief that additional fiber will absorb excess water and thus improve stool consistency. For the occasional patient who has IBS, additional fiber does seem to improve stool consistency to some degree, making it less loose. But for most people who have IBS and diarrhea, fiber only seems to make symptoms worse. So, the first step for most individuals who have IBS and diarrhea is to eliminate any fiber supplements from their diet, especially over-the-counter products and nutritional supplements. This simple step generally leads to a significant improvement in symptoms. When further improvement is needed, following a diet that is low in fiber usually produces further improvement. Such a diet emphasizes lean proteins and small to moderate portions of carbohydrates, with a small amount of natural fiber for nutritional balance. As discussed in Chapter 15, the low-FODMAP diet can also improve symptoms in many patients who have IBS and diarrhea.
Caffeine is greatly enjoyed by most adults in coffee, tea, and soft drinks. However, caffeine can stimulate the GI tract. For many people, that cup or two of morning coffee predictably stimulates a bowel movement. For people who have constipation, this characteristic of coffee can be used to their advantage. However, for those who have diarrhea, caffeine may worsen diarrhea and cause cramps and spasms. Since caffeine is addictive, if you take in a lot of caffeine each day you should not eliminate caffeine all at once, as you may suffer from mild withdrawal symptoms. These symptoms include headaches, restlessness, agitation, anxiety, disturbed sleep, and moodiness. When asked to keep track of their caffeine intake, some people are surprised by the amount they consume each day. Two cups of coffee in the morning, one cup of coffee for a mid-morning and mid-afternoon break, and two or three soft drinks during the day add up to a significant dietary load of caffeine. A slow withdrawal from caffeine usually leads to some improvement in diarrhea and feelings of bowel urgency; this can be done by slowly decreasing the number of servings each day or by gradually substituting decaffeinated coffee and soft drinks.
As noted in the case study presented in Chapter 14, many medications are available over the counter or by prescription and may provide significant relief of symptoms, but they can also cause side effects. Finding the correct medication for you—one that alleviates your symptoms without intolerable side effects—may take some trial and error. The process begins by listing any medications (for any condition) and any supplements or herbal preparations that you are currently using and all the treatments for diarrhea that you have tried in the past. Many of the medications used in treating diarrhea are listed in Table 17.1. The way they work and their side effects are described below.
Loperamide. Loperamide (Imodium) is now the first choice for treating intermittent diarrhea. It first became available over the counter in liquid form in 1988 and in caplet form a year later. Loperamide is a very mild opiate (a type of narcotic). However, because only a small portion of it enters the brain, because the dose is small, and because the drug is rapidly broken down by the liver, the common side effects of narcotics (sedation, mental clouding, confusion, euphoria, respiratory depression, and addiction) are rarely encountered.
Loperamide slows the transit of materials through the intestinal tract, thereby allowing more fluid to be absorbed. It also slightly increases muscle tone in the anal canal, which can be helpful to people experiencing fecal soiling or fecal incontinence. Each caplet contains 2 mg of loperamide, and each teaspoonful (5 ml) of the liquid preparation contains 1 mg. A typical starting dose is 2 mg; for severe diarrhea, patients can take up to 8 pills a day for brief periods of time. Care should be taken to discontinue loperamide as soon as diarrhea is controlled, to avoid inducing constipation, especially in people who have IBS and are prone to alternating constipation and diarrhea.
Loperamide is not recommended for people who have inflammatory bowel disease (ulcerative colitis or Crohn’s disease), because it may cause a condition called toxic megacolon. Loperamide should not be taken during the early stages of an infectious diarrhea. Diarrhea is one way the body eliminates toxins so, although diarrhea is unpleasant, during the initial stages of an infectious diarrhea it is important not to slow down the GI tract, since this would delay the evacuation of the infection from the body.
Table 17.1. Medications Used to Treat Diarrhea
Bulk-forming agents (fiber products) Psyllium (Metamucil) Methylcellulose (Citrucel) Calcium polycarbophil (Equalactin, FiberCon) 5-HT3 antagonists Alosetron (Lotronex) Bismuth products Bismuth subsalicylate (Pepto-Bismol) Opiates Loperamide (Imodium) Diphenoxylate-atropine (Lomotil) DTO (deodorized tincture of opium) Anticholinergic agents Atropine Dicyclomine (Bentyl) Hyoscyamine (Levsin, LevBid, NuLev) Scopolamine Resin-binding agents Cholestyramine (Questran) Tricyclic antidepressants Amitriptyline (Elavil) Nortriptyline (Pamelor) Desipramine (Norpramin) Imipramine (Tofranil) Herbal preparations Agrimony (Agrimonia eupatoria) Bilberry (Vaccinium myrtillus) Blackberry (Rubus fruticosus) Cinquefoil (Potentilla erecta) Jambolan (Syzygium cumini) Lady’s mantle (Alchemilla vulgaris) Uzara (Xysmalobium undulatum) |
Many individuals who have IBS and diarrhea use loperamide prophy-lactically, to prevent episodes of fecal incontinence or minimize the risk of having diarrhea while traveling. This strategy can be especially helpful for people who have IBS and diarrhea who suffer from severe fecal urgency. In these patients, 1 to 2 mg of loperamide 45 minutes before a meal can significantly improve the heightened gastrocolic reflex that leads to the feelings of urgency after eating a meal. This prophylactic dosing should be done only when bowel patterns are well known, when the person’s response to the medication has been established, and after discussions between patient and physician.
Although loperamide is widely used by people who have IBS and diarrhea and has been well tested in the general population, no large research studies have evaluated its benefits for the IBS population. Finally, while loperamide may improve diarrhea, it does not help the bloating and abdominal pain that typify IBS.
Pepto-Bismol. This inexpensive pink liquid has been around since 1901 and is a favorite of many people for treating mild cases of GI upset (indigestion, heartburn, fullness in the upper abdomen, nausea, or diarrhea). The active ingredient in Pepto-Bismol is bismuth subsalicylate. Although the exact mechanism of action of bismuth subsalicylate is unknown, it may have both mild anti-inflammatory properties and antimicrobial (antibacterial) activities. In addition, Pepto-Bismol contains a small amount of claylike particles (silicon dioxide), and it is possible that these bind to toxins in the GI tract and keep them from stimulating or inflaming the GI tract. For some people, Pepto-Bismol improves pain, fullness, and bloating in the upper GI tract as it coats the lining of the stomach. It is available in both liquid form (262 mg of bismuth subsalicylate per tablespoon [15 ml]) and tablet form (262 mg per tablet).
Although large-scale studies have not been performed to evaluate the efficacy of Pepto-Bismol for people who have IBS, several small double-blinded (when neither the patients nor the practitioners know until the end of the study who is receiving the medication versus the placebo), placebo-controlled studies have shown that it does relieve diarrhea in a general population of people with that symptom. This medication is generally considered safe for short-term use. Long-term use is not recommended, because it has the potential to cause several dangerous conditions (among them, salicylate toxicity, encephalopathy), especially in patients who have abnormal kidney function. Pepto-Bismol can turn the stool dark, which is often distressing to patients, especially since very dark stool can be a sign of internal bleeding, but this side effect is harmless.
Probiotics. You can barely open a newspaper now or turn on the television without seeing or hearing something new about probiotics. Although these agents are now widely used (and also misused) for a variety of ailments and conditions, a lot of misinformation about probiotics remains. Probiotics are live microorganisms which, when administered in an adequate amount, are intended to confer a health benefit to the host (the patient). There are a number of probiotics now available to consumers. Most are sold over the counter, although some are available only by prescription. Some of the most commonly used probiotics include strains (types) of lactic acid bacilli (e.g., Lactobacillus, Bifidobacterium, and Lactococcus). Other commercially available probiotics include strains of the bacteria E. coli Nissle 1917, Clostridium butyricum, Streptococcus thermophilus, Streptococcus salivarius, Bacillus coagulans, and Enterococcus faecium. Finally, some probiotics are nonpathogenic (not dangerous to the host) strains of yeast (e.g., Saccharomyces boulardii and Saccharomyces cerevisiae).
Although the discussion about the use of probiotics for the treatment of IBS symptoms is fairly new, the concept of using “good” microbes to improve intestinal health, and possibly even general well-being, has been around for quite some time. More than one hundred years ago, the Nobel Prize winner Elie Metchnikoff hypothesized that the consumption of yogurt, which contained the bacteria (the probiotic) Lactobacillus, was responsible for the increased longevity of eastern Europeans.
Probiotics are available in many different forms. They may be found naturally in food products such as yogurts and fermented milk, and they are now added to food bars, cereals, and even some baby formulas. Probiotics are also readily available over the counter in the form of capsules, pills, and powders. The amount of the probiotic bacteria is usually lower in naturally probiotic foods than in prescribed and over-the-counter pro-biotic products.
One question that patients commonly ask is, “How do probiotics work?” The honest answer is that no one really knows at present. Many different theories exist, and it is quite possible that probiotics work differently in different people (which may explain why probiotics seem to work so well for some people who have IBS but not for others). Probiotics may improve gastrointestinal symptoms by improving the immune system of the GI tract; suppressing the growth of harmful bacteria; improving the absorption of important vitamins and minerals; and/or producing products that maintain the health of the cells that line the colon. Although it may seem odd to recommend a product to a patient without knowing exactly how it works, there are good data to show that probiotics do work (see below), and this lack of knowledge shouldn’t stop physicians from recommending something that can improve individuals’ symptoms of IBS.
A good example of a patient who might benefit from a probiotic is someone who develops IBS symptoms after a viral gastroenteritis (such as postinfectious IBS). If you recall from our discussion in Chapter 3, some patients develop IBS symptoms after an infectious illness. In these people, the infection may have changed the normal composition of the gut flora (the bacteria that normally reside in the large intestine). The theory is that a “good” bacteria (such as a probiotic) can be added back to the GI tract to slowly restore the natural balance of bacteria in the large intestine. In support of this theory, some data show that the composition of the intestinal flora is different in patients who have IBS compared to those who don’t. Unfortunately, we are not yet able to precisely measure the type and content of bacteria in everyone’s colon. It is possible that in the future we will be able to measure colonic bacteria accurately enough that we can diagnose an individual with a specific deficiency of one gut bacteria or another and then make a specific recommendation about a probiotic that contains the missing bacteria.
As you read labels of probiotic products, remember that although many different probiotics have been recommended for patients who have IBS, most have not been specifically tested in such patients. Many probiotics make strong claims with little if any real data to support those claims. Because probiotics are currently considered food and dietary supplements, they are not strictly regulated by the FDA. In contrast to medications that have been FDA approved for the treatment of IBS, probiotics do not have to undergo rigorous testing or evaluation in clinical trials to assess their efficacy and safety.
Despite the lack of FDA regulation, two types of probiotics are worth mentioning here. Bifidobacterium infantis 35624, sold over the counter as Align, has been tested in two large placebo-controlled trials with patients who have IBS. Patients treated with Align showed a significant improvement in IBS symptoms of bloating, diarrhea, and pain, compared to those treated with a placebo. Align should be used once daily for at least 90 days to determine whether it can improve IBS and diarrhea symptoms. In addition, the product VSL#3 (which contains eight different strains of bacteria) appears to slow movement of materials through the large intestine and may improve symptoms of diarrhea and bloating in patients who have IBS and diarrhea. (See Chapter 20 for a discussion of the limitations and safety of probiotics.)
Antibiotics. One of the most interesting areas of research in the field of IBS during the last few years has been that of antibiotics for the treatment of IBS. This type of treatment is somewhat unusual, because patients who have IBS do not have an active infection in their GI tract that is the cause of their symptoms. However, as described earlier, one hypothesis about the development of IBS symptoms is that the normal gut flora (the normal content of bacteria in the large intestine) has been changed, possibly by an infection that has long since resolved. The treatment theory is that a course of antibiotics may again alter the balance or content of bacteria within the colon, thereby improving IBS symptoms. Alternatively, some researchers and clinicians believe that IBS symptoms develop due to the condition called SIBO (small intestine bacterial overgrowth; see Chapter 11). If this hypothesis is correct, then using antibiotics to treat the bacteria that inappropriately reside within the small intestine makes sense.
The best-studied antibiotic for the treatment of IBS with diarrhea is rifaximin. Rifaximin is a unique antibiotic because nearly all of it stays within the GI tract. In fact, less than 0.4 percent is absorbed from the GI tract, which makes it very safe. In addition, rifaximin is known to act on many of the bacteria that inhabit the large intestine (these are grouped under the categories of gram negative rods and anaerobes). Although the exact mechanism for why rifaximin improves IBS with diarrhea symptoms is unknown (Does it treat SIBO? Does it change colonic flora? Does it temporarily lower the bacterial content of the colon?), the results of five large, well-designed research studies have shown that patients who had IBS and were treated with rifaximin felt significantly better than patients who had IBS and were treated with a placebo pill. For the treated individuals, symptoms of bloating improved, as did symptoms of abdominal pain and diarrhea. Based on these five studies, the ideal IBS population for rifaximin treatment is composed of patients who have IBS with diarrhea or patients who have IBS with mixed symptoms of diarrhea and constipation. Occasionally, treatment with rifaximin can cause constipation in some patients; therefore, this medication is not recommended for people who have IBS and constipation.
According to the research, the most appropriate dosage of rifaximin is 550 mg taken 3 times daily for 14 days. Patients who have a positive response to rifaximin may expect an improvement in IBS symptoms for three to six months. Rifaximin is the first medication used to treat IBS (of any type) in which a patient only needs to be treated for a short time (just two weeks) but will still be experiencing benefits three to six months later. Although rifaximin has not yet been approved by the FDA for the treatment of IBS, a large multicenter study is currently under way. If the study results are positive, physicians are hopeful that rifaximin will be approved and available for patients who have IBS.
All of the medicines described below slow down the gastrointestinal tract by some means, so they should be used with care and close physician consultation by people who have IBS and alternate between diarrhea and constipation.
Lomotil. Lomotil is a brand name prescription medication consisting of diphenoxylate hydrochloride and atropine. Diphenoxylate is similar to loperamide in that it is a mild narcotic and works by slowing down the GI tract. When the GI tract is slowed down, more water can be absorbed, which leads to less frequent and more formed bowel movements. In addition, diphenoxylate may decrease the secretion of fluid into the GI tract. Atropine is classified as an anticholinergic agent (see below). It works throughout the GI tract to slow motility and also blunts the strong contractions of the colon and small bowel that are perceived as spasms and cramps.
Some patients find that Lomotil works better than Imodium to treat their diarrhea, especially if they suffer from persistent abdominal cramps and spasms. Lomotil, like Imodium, will not help with bloating due to IBS. However, in contrast to loperamide, a slight potential for becoming addicted to the diphenoxylate component exists. Also, because of the anticholinergic effects (the atropine component), Lomotil can cause some people to suffer from a dry mouth and to develop a rapid heart rate (tachycardia).
DTO (deodorized tincture of opium). Tincture of opium is essentially a liquid preparation of opium (along with a small amount of deodorant to help disguise the unpleasant taste). Since it is a narcotic, DTO, like loperamide and diphenoxylate-atropine, slows the GI tract and promotes fluid absorption from the colon. Because it is more addictive, this prescription medication is generally reserved for patients who fail to get relief from maximum doses of loperamide or diphenoxylate-atropine. The typical starting dose is one or two drops each morning in a small amount of water or juice. Patients then monitor their symptoms and, if necessary, may slowly increase the dose by an additional drop or two each morning. Patients report that DTO does not help with the pain, gassiness, or bloating of IBS.
Anticholinergic agents. This term encompasses a large group of fairly similarly acting prescription medications; some of the most common are atropine, scopolamine, and dicyclomine. Anticholinergic agents block the actions of acetylcholine, a neurotransmitter involved in gut motility. More specifically, acetylcholine is one of the major chemicals that initiate and maintain smooth-muscle contraction in the GI tract. When the actions of acetylcholine are blocked, the smooth muscle of the GI tract relaxes and quiets down. This leads to a slowing of gut motility and increased fluid absorption from the GI tract.
Unlike with opiates, there is no potential for addiction with anticholinergic agents. However, because these medications act throughout the entire body, not just in the GI tract, side effects can develop, especially with larger doses. These side effects include dry mouth, dry eyes, changes in vision, difficulty urinating, fatigue, sleepiness, and, rarely, constipation.
Cholestyramine. This prescription medication, classified as a resin-binding agent, functions very differently from all of the substances discussed above. It acts by binding to bile acids, which are important to the digestive process because they help absorb fats. Bile acids are formed in the liver, pass through the bile duct, and are emptied into the small intestine, where they help to absorb fats. In some patients, bile acids can cause diarrhea, if they irritate the lining of the colon and stimulate colonic motility.
Cholestyramine is generally started at a small dose once or twice a day and then gradually increased to four times a day, if necessary. It is available in both individual-dose packets and in a large can; the brand name is Questran. Although cholestyramine has never been studied with a large group of people who have IBS, it has been proven to help people who have other types of chronic diarrhea. Cholestyramine is considered safe, although if used for long periods of time or at high doses, cholestyramine has the potential to bind to certain medications and vitamins, causing them to be excreted from the body without being properly absorbed.
Tricyclic antidepressants (TCAs). This class of prescription medications was used for many years to treat depression, although in retrospect, they were not very effective at treating symptoms of depression in most people. Newer agents (the SSRIs—see Chapter 22) have nearly completely replaced TCAs in the treatment of depression. However, TCAs are often very effective in relieving some of the symptoms of IBS and diarrhea, if carefully used at low to moderate doses. TCAs tend to slow colonic transit to some degree and thus decrease the frequency of bowel movements. In addition, these agents seem to blunt or block some of the strong contractions in the GI tract of people who have IBS and diarrhea. Thus, many patients find a significant improvement in bowel urgency, spasms, pain, cramps, and diarrhea when treated with TCAs.
The relief of IBS symptoms is itself a side effect of TCAs, for that was not their intended function, but they also have a number of undesirable side effects, especially if used at the high doses typically required for patients who have severe IBS symptoms. These side effects, which include constipation, sedation, dry mouth, dry eyes, and urine retention, are all related to their anticholinergic action (see above), and they make taking the drug unpleasant for many patients. Some of the TCAs most commonly prescribed for relief of IBS symptoms are listed in Table 17.1.
Alosetron. Alosetron (sold as Lotronex) is a 5-HT3 antagonist. Alosetron works by blocking the action of serotonin at specific receptors in the GI tract. Excess serotonin can lead to overstimulation of the GI tract, causing rapid transit of material through the intestines and the generation of strong muscular contractions in both the colon and small intestine. Serotonin receptors are located throughout the GI tract. The concept of blocking a specific receptor is based on the “lock and key” model: if a specific receptor site (the lock) is physically blocked by an antagonist molecule (such as a medication), then the neurotransmitter molecule (the key) that normally fits into the lock cannot attach, and the receptor cannot receive its message and be activated. In this case, serotonin cannot attach to its specific receptor, because the receptor site is blocked by alosetron. If serotonin cannot bind to its receptors, then it cannot speed up gut motility and initiate strong muscular contractions, a process important in the development of symptoms of IBS with diarrhea.
For women who have diarrhea-predominant IBS, alosetron has been shown to be effective at treating many of the common symptoms of IBS. (Too few men participated in the original studies for the reports to make scientifically sound statements about the drug’s effectiveness in men.) Women treated with this prescription drug noted a significant improvement in their diarrhea, a reduction in their level of abdominal pain, and an improvement in the sense of urgency associated with having a bowel movement. These results were demonstrated in four large, randomized, double-blind, placebo-controlled studies involving thousands of patients. A panel of experts from the American College of Gastroenterology (a professional organization composed of nearly ten thousand gastroenterologists and researchers) noted that alosetron provided a significant reduction in all the symptoms of diarrhea, abdominal pain, and bloating in patients who have IBS and diarrhea. Many women who had tried and not been helped by traditional therapies noted a dramatic improvement in their IBS symptoms while taking alosetron.
Alosetron is currently available for use under an RMP (Risk Management Program). Approximately 280 medications on the market are available under an RMP. This program requires that if your doctor prescribes alosetron to you, you sign a form saying that she or he reviewed the risks and benefits of this medication with you (please note that the risks and benefits of every medication should always be explained to you, not just for alosetron). Alosetron is part of an RMP because a few study individuals who had IBS and diarrhea became very constipated or possibly developed an uncommon condition called ischemic colitis after taking alosetron. Ischemic colitis is a condition in which there is a reduction in blood flow to the colon, which can lead to pain and bloody diarrhea. The risk of developing ischemic colitis while taking alosetron is quite low—about one in one thousand. Approximately one thousand people who have IBS and diarrhea would need to be treated with alosetron before one of those patients developed ischemic colitis. When ischemic colitis does occur (either in a patient who has IBS or in any other patient), it generally resolves on its own without any long-term effects after the patient stops taking alosetron. Research has shown that, in general, people who have IBS are at increased risk for ischemic colitis—it is not solely associated with those people who have IBS and are taking alosetron.
If your doctor decides that alosetron may be the right medication for you, then you can become a part of the prescribing program for Lotronex. You will need to sign a consent form and stay in contact with your doctor. Since this program was instituted, there have not been any major adverse reactions to alosetron. This highlights the fact that, when a knowledgeable health care provider prescribes this medication for an appropriate patient (such as a woman who has IBS and diarrhea), it is quite safe.
Herbal agents. A number of herbal preparations for the treatment of diarrhea are currently on the market (see Table 17.1). None of these herbal remedies has been subjected to double-blind, placebo-controlled trials for any large group of people who have diarrhea, and none has been tested in a research setting by patients who have IBS and diarrhea. However, they are now frequently used by people who have IBS. If you decide to try an herbal remedy, you should buy it from a reputable source and make sure that it is in a pure form, rather than mixed with a variety of other agents. In addition, you should talk to the owner or manager of the health food store or pharmacy where you purchase these agents, to evaluate that person’s professional knowledge of the use of the medication. If you have friends who have used the product, you should talk to them about their experience. Follow the printed directions carefully, and start at the lowest dose you can, slowly increasing the amount without exceeding the dosage on the instructions. Let your primary care doctor know that you are going to try the product, and contact him or her if you notice any change in your health. It is possible that one of these agents will improve your diarrhea, but given the absence of research on these substances, and given the complicated nature of IBS, don’t be surprised if these agents do not improve other symptoms of IBS, like abdominal pain, bloating, and distention, even if they do ease the diarrhea.
• Diet can play a significant role in IBS with diarrhea.
• Patients who have IBS and diarrhea should carefully review their intake of caffeine, lactose, fructose, sorbitol, and fiber, because these can all worsen diarrhea.
• The medical treatment for diarrhea focuses on slowing transit through the GI tract. This allows better absorption of water, the formation of more-solid stool, and less frequent bowel movements.
• Loperamide (Imodium) and diphenoxylate-atropine (Lomotil) are both very mild narcotics that can improve diarrhea by slowing the GI tract. They are usually not effective at treating the abdominal pain or bloating frequently experienced by patients who have IBS and diarrhea.
• Probiotics are being extensively studied with patients who have IBS. The probiotic Align has been shown to improve IBS and diarrhea symptoms in two large, well-designed studies.
• Antibiotics may help some patients who have IBS and diarrhea, but they need to be chosen carefully, because many antibiotics can worsen IBS and diarrhea symptoms.
• Alosetron is the only medication currently approved by the FDA for the treatment of IBS with diarrhea. It has been shown to be safe and effective for many patients who have IBS and diarrhea.