Gastrointestinal Tract

A common disorder is the inflammation of the lining of the stomach or intestine (gastroenteritis), usually the result of an infection or parasitic infestation. Damage can also be done by the inappropriate production of digestive juices, leading to minor complaints like acidity and major disorders like peptic ulcer. The lining of the intestines can be damaged by inflammation (inflammatory bowel disease). The rectum and anus can become painful and irritated by damage to the lining, tears in the skin at the opening of the anus (anal fissure), or enlarged veins (hemorrhoids).

The most frequent gastrointestinal disorders, constipation and diarrhea, usually occur when something disrupts the normal muscle contractions that propel food residue through the bowel.

Antacids

Digestive juices in the stomach contain acid and enzymes that break down food before it passes into the intestine. The wall of the stomach is normally protected from the action of digestive acid by a layer of mucus that is constantly secreted by the stomach lining. Problems arise when the stomach lining is damaged or when too much acid is produced and eats away at the mucous layer. Excess acid leading to discomfort, commonly referred to as indigestion, may result from overeating, drinking coffee or alcohol, smoking, anxiety, or, in some people, from eating certain foods. Some medicaments, notably ASA and non-steroidal anti-inflammatory medicaments, can also irritate the stomach lining and even cause ulcers.

Antacids are used to neutralize acid and thus relieve pain. The types most regularly used are those that contain magnesium and aluminum. Some antacids contain calcium.

By neutralizing stomach acid, antacids prevent inflammation, relieve pain, and allow the mucous layer and lining to mend. When used in the treatment of ulcers, they prevent acid from attacking damaged stomach lining and so allow the ulcer to heal.

If antacids are taken according to instructions, they are usually effective in relieving abdominal discomfort caused by acid. The speed of action varies depending on the ability to neutralize acid. Their duration of action also varies; short-acting medicaments may have to be taken quite frequently. Although most antacids have few serious side effects when used only occasionally, some may cause diarrhea, and others may cause constipation.

Antacids should not be taken to prevent abdominal pain on a regular basis except under medical supervision, as they may suppress the symptoms of a serious disorder. Prolonged use of any antacid can cause an increase in the production of stomach acid when treatment is stopped suddenly.

All antacids can interfere with the absorption of other medicaments. For this reason, if you are taking a prescription medicine, you should check with your physician before taking an antacid.

Anti-ulcer medicaments

Normally, the linings of the esophagus, stomach, and duodenum are protected from the irritant action of stomach acids by a layer of mucus. If this layer becomes damaged, stomach acid may erode the underlying tissue, causing a peptic ulcer. This usually leads to abdominal pain, vomiting, and loss of appetite. Duodenal ulcers, the most common peptic ulcers, are usually less of a problem than other types.

The exact cause of peptic ulcers is not understood, but certain predisposing factors have been identified; these include heavy smoking, the regular use of ASA or similar medicaments, the overuse of alcohol and coffee, and a stressful lifestyle combined with irregular and rushed meals. A bacterium called Helicobacter pylori, found in the majority of patients with duodenal ulcers, is now thought to be a causative agent. The usual first-line treatment is with either an H2 blocker (cimetidine, famotidine, nizatidine, or ranitidine) or other anti-ulcer medicament such as misoprostol, omeprazole, pirenzepine, or sucralfate.

Medicaments protect ulcers from the action of stomach acid, thereby allowing the underlying tissue to heal. H2 blockers, misoprostol, omeprazole, and pirenzepine reduce the amount of acid released into the stomach, whereas sucralfate forms a protective coating over the ulcer. Misoprostol and pirenzepine also have a protective action.

These medicaments begin to reduce pain within a few hours, and in most cases allow the ulcer to heal in four to eight weeks. They produce few side effects, although one of the H2 blockers, cimetidine, can cause confusion in the elderly, particularly if the stated dose is exceeded. Sucralfate may cause constipation, and misoprostol diarrhea. Because these medicaments may mask symptoms of cancerous stomach ulcers, they are normally prescribed only when stomach cancer has been ruled out.

The H2 blockers are not usually prescribed for courses of more than six months because their safety over prolonged periods is not established. Long-term therapy with omeprazole is also not recommended. Sucralfate is prescribed for up to eight weeks at a time; it may interfere with absorption of fats and so reduce the absorption of vitamins A, D, E, and K, which are dissolved in fat. Prolonged use may require vitamin supplements.

Antidiarrheal medicaments

Diarrhea is an increase in the fluidity and frequency of bowel movements. In some cases diarrhea protects the body from harmful substances in the intestine by hastening their removal. The most common causes of diarrhea are viral infection, food poisoning, and parasites. But diarrhea also occurs in other illnesses. It can be a side effect of some medicaments and may follow radiation therapy for cancer. Diarrhea may also be caused by anxiety.

An attack of diarrhea usually clears up quickly without medical attention. The best treatment is to abstain from food and to drink plenty of clear fluids. Rehydration solutions containing sugar and potassium and sodium salts are recommended for preventing dehydration and chemical imbalances, particularly in children. You should consult your physician if: the condition does not improve within 48 hours; the diarrhea contains blood; there is severe abdominal pain and vomiting; you have just returned from a foreign country, or if the diarrhea occurs in a small child or an elderly person.

Severe diarrhea can impair absorption of medicaments, and anyone taking a prescription medicine should call a physician. A woman taking oral contraceptives may need to take additional contraceptive measures.

Nonspecific diarrhea may be relieved by medicaments that act directly on the bowel (narcotics, loperamide), or by bulk-forming and adsorbent agents. Antispasmodic medicaments may also be used to relieve pain.

Each type of antidiarrheal medicament works differently. Narcotic medicaments decrease the propulsive activity of the muscles so that fecal matter passes more slowly through the bowel.

Bulk-forming agents and adsorbents take on water and irritants present in the bowel, thus producing larger and firmer bowel movements less frequently.

Medicaments used to treat diarrhea reduce the urge to move the bowels. Narcotic medicaments and antispasmodics may relieve abdominal pain. All antidiarrheals may cause constipation if used in excess.

Used in relatively low doses for a limited period of time, the narcotic medicaments are unlikely to produce adverse effects. However, these medicaments should be used with caution when diarrhea is caused by an infection, since they may slow the elimination of microorganisms from the intestine. All antidiarrheals should be taken with plenty of water. It is important not to take a bulk-forming agent together with a narcotic or antispasmodic medicament, because a bulky mass could form and obstruct the bowel.

Laxatives

When your bowels do not move as frequently as usual and the movements are hard and difficult to pass, you are suffering from constipation. The most common cause is the lack of sufficient fiber in your diet; fiber supplies the bulk that makes the feces soft and easy to pass. The simple remedy is more fluid and a diet higher in fiber, i.e., more fruits, vegetables, and whole grain breads. Constipation is commonly relieved by laxatives, although some physicians recommend occasional small enemas.

Ignoring the urge to defecate can also cause constipation, the feces becoming dry (and hard to pass) and too small to stimulate the muscles that propel them through the intestine. Certain medicaments may be constipating such as narcotic analgesics, tricyclic antidepressants, and antacids containing aluminum. Some diseases, such as hypothyroidism, can lead to constipation.

Because constipation may be a symptom of something serious, consult your physician about any change in bowel habits that lasts more than a week.

Laxatives act on the large intestine -by increasing the speed with which fecal matter passes through the bowel or increasing its bulk and/or water content. Stimulants cause the bowel muscle to contract, increasing the speed with which fecal matter passes through the intestine. Bulk-forming laxatives absorb water in the bowel, thereby increasing the volume of fecal matter and making bowel movements softer and easier to pass. Lactulose also causes fluid to accumulate in the intestine. Saline laxatives prevent water from passing out of the large intestine by osmotic action without increasing the bulk of bowel movements. Lubricant mineral oil preparations and stool softeners make the bowel movements softer and easier to pass without increasing their bulk. But prolonged use of mineral oil leaves a coating that can interfere with absorption of some essential vitamins.

Laxatives can cause diarrhea if taken in overdose, and constipation if overused. The most serious risk of prolonged use of most laxatives is developing dependence on the laxative for normal bowel action. Use of a laxative should therefore be discontinued as soon as normal bowel movements have been reestablished. Children should not be given laxatives except in special circumstances on the advice of a physician.

Medicaments for inflammatory bowel disease

"Inflammatory bowel disease" is the term used to describe certain disorders in which the wall of the intestine and other parts of the gastrointestinal tract become inflamed, causing symptoms that include periodic attacks of pain, general feelings of ill-health, and often diarrhea that is sometimes bloody. Loss of appetite and poor absorption of food often result in weight loss.

Although the exact cause of these disorders is unknown, the risks and severity of attacks are increased by some infections, antibiotics, and excessive stress.

Physicians identify two main types of inflammatory bowel disease: Crohn's disease and ulcerative colitis. In Crohn's disease (also called regional enteritis) any part of the digestive tract may be inflamed, although the small intestine and the colon are the most commonly affected sites. In ulcerative colitis the large intestine becomes inflamed and ulcerated, often producing blood-stained diarrhea.

Corticosteroids, mesalamine (5-aminosalicylic acid), sulfasalazine, and metronidazole are used to treat Crohn's disease and the first three agents are used in ulcerative colitis. Rarely, immunosuppressant medicaments such as azathioprine are used in both conditions. Nutritional supplements are frequently given in Crohn's disease. Antidiarrheal agents are given with great caution. In severe cases, surgery may be necessary.

Corticosteroids, sulfasalazine, and mesalamine depress the inflammatory process, thus allowing the damaged tissue to recover. They act in different ways to prevent migration of white blood cells into the bowel wall, which may be responsible in part for the inflammation of the bowel.

Taken to treat attacks, these medicaments relieve symptoms within a few days, and general health improves gradually over a few weeks. Sulfasalazine and mesalamine are usually effective in providing longer-term relief from the symptoms of ulcerative colitis. Immunosuppressants are reserved for the treatment of severe disease that has not responded to other medications and are administered under strict medical supervision.

Immunosuppressant and corticosteroid medicaments can cause serious adverse effects and they are thus only prescribed when potential benefits outweigh the risks involved.

It is important to continue taking these medicaments as instructed because stopping them abruptly may cause a sudden flare-up of the disorder. Physicians usually supervise a gradual reduction in dosage when stopping the medicament, even when given as a short course to treat an attack. Antidiarrheal medicaments should not be taken on a routine basis because they may mask signs of deterioration or even aid sudden bowel dilation or rupture.

Medicaments for rectal and anal disorders

The most common disorder affecting the rectum (the last part of the large intestine) and anus (the opening from the rectum) is hemorrhoids, commonly called piles. They occur when hemorrhoidal veins become swollen, irritated, or clotted, often the result of prolonged local back pressure such as that caused by a pregnancy or a job requiring long hours of sitting. Hemorrhoids may cause irritation and pain, especially on defecation. The condition is aggravated by constipation and straining while passing a bowel movement. Sometimes hemorrhoids may bleed and occasionally clots may form in the swollen veins, leading to severe pain, a condition called thrombosed hemorrhoids.

Other common disorders affecting the anus include anal fissure (painful cracks in the anus) and pruritus ani (itching around the anus).

A number of over-the-counter and prescription-only preparations are available for the relief of such disorders. Warm, herbal sitz baths also help.

The main risk is that self-treatment of hemorrhoids may delay diagnosis of a more serious bowel disorder. It is therefore always wise to consult your physician if you have symptoms of hemorrhoids, especially if you have noticed rectal bleeding.

Medicaments treatment for gallstones

The formation of gallstones is the most common disorder of the gallbladder, which is the storage and concentrating unit for bile, a digestive juice produced by the liver. During digestion, bile passes from the gallbladder via the bile duct into the small intestine, where it aids the digestion of fats. Bile is made up of several ingredients, including bile acids, bile salts, and bile pigments. It also contains significant amounts of cholesterol dissolved in bile acid. If the amount of cholesterol in the bile increases or if that of bile acid is reduced, a proportion of the cholesterol cannot remain dissolved. This excess may accumulate in the gallbladder as gallstones.

Gallstones may be present in the gallbladder for years without causing symptoms. However, if they become lodged in the bile duct they cause pain and block the flow of bile, which could result in infection and inflammation.

Gallstones containing mostly cholesterol can be dissolved using medicament therapy. However, when stones contain significant amounts of other material, such as calcium, or if a stone becomes lodged in the bile duct, surgical removal may be required. The most commonly used gallstone-dissolving medicament is ursodiol.

Ursodiol is a substance that is naturally present in bile. It acts on chemical processes in the liver to regulate the amount of cholesterol in the blood, by controlling the amount that passes into the bile. Once the level of cholesterol in the bile is reduced, the bile acids are able to start dissolving the stones in the gallbladder. For maximum effect, ursodiol treatment usually needs to be accompanied by adherence to a low-cholesterol, high-fiber diet.

Medication treatment may take up to two years, or longer, to dissolve gallstones completely. You will not, therefore, feel any immediate benefit from the medicaments, but you may have some minor side effects, the most usual of which is diarrhea. If this occurs, your physician may adjust the dosage. The effect of medicament treatment on the gallstones is usually monitored regularly by means of ultrasound or X-ray examinations.

Even after successful treatment with medicaments, this condition can recur when ursodiol is stopped. In some cases medicament treatment and dietary restrictions may be continued after the gallstones have dissolved, in order to prevent a recurrence of the problem.

Ursodiol is not usually given to people with liver disorders because it can interfere with the normal liver function.

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