Pharm7e-Ch12-Presentation

[Audio] Welcome to the Pharmacology for Technicians Seventh Edition Watch and Learn Lessons!.

[Audio] Chapter 12, The Gastrointestinal System and Drug Therapy.

[Audio] In section 12.1, you will learn about anatomy and physiology of the gastrointestinal system. Throughout this chapter, you will develop an understanding of drug treatments for GI diseases. You will learn about gastroesophageal reflux disease and its complications. In the diarrhea and drug treatment section, you will get an overview of antidiarrheal agents and their mechanisms of action. In the constipation and flatulence and drug treatments section, you will learn about the role of fiber in the digestive process. You will also learn about laxatives and their mechanisms of action in that section..

[Audio] In the nausea and vomiting and drug treatment section of this chapter, you will be introduced to the chemoreceptor trigger zone and learn about its role in nausea. You will also get an overview of antiemetics that act on the CTZ and their mechanisms of action. In the last section of this chapter, hepatitis and drug treatments, you will discover measures to prevent and treat hepatitis..

[Audio] Chapter 12, Section 1, Anatomy and Physiology of the Gastrointestinal System.

[Audio] The gastrointestinal or GI system is a group of organs that process food and liquids. It is composed of the GI tract and other organs and supportive organs. The GI tract is a tube that begins in the mouth; extends through the pharynx, esophagus, stomach, small intestine, and large intestine; and ends at the anus. As food travels through this tube, the GI tract converts complex food substances into simple compounds through the process of digestion. These compounds can then be absorbed into the bloodstream and used by the cells of the body. This process is called absorption. In addition, the GI tract excretes solid waste. The time it takes for material to pass from the mouth to the anus is referred to as GI transit time..

[Audio] Once food is ingested into the mouth and passes through the esophagus, it enters the stomach. This organ produces gastric juice which breaks down food. This material then travels to the small intestine, which absorbs most of its nutrients. Next, the material enters the large intestine or colon. The large intestine absorbs water..

[Audio] Several organs release secretions that help the body digest and absorb nutrients. The salivary glands produce saliva which lubricates food, making swallowing easier. Saliva also contains enzymes that begin digesting carbohydrates. The gallbladder is a holding area where bile is stored. Bile is produced by the liver and aids digestion and absorption of fat and cholesterol from the small intestine. The pancreas produces many enzymes that help digest carbohydrates, fats, and proteins. It releases secretions that neutralize stomach acid. The liver produces bile and removes harmful substances before they reach general circulation..

[Audio] Chapter 12, Section 2, Gastrointestinal Reflux Disease and Drug Treatments.

[Audio] Gastroesophageal reflux disease, or GERD, is commonly referred to as heartburn. It is caused by the reflux of acidic stomach contents through an incompetent lower esophageal sphincter. Symptoms of GERD include a burning feeling or pain in the upper abdomen and chest, acid taste, and food regurgitation. Regurgitation is when swallowed food goes back up through one's throat. Patients may also experience a gnawing or burning that is worse before meals and may wake them up from sleep..

[Audio] Figure 12.4 compares a normal esophageal sphincter which closes after each swallow, shown on the left, with an incompetent esophageal sphincter, shown on the right. The incompetent esophageal sphincter does not close completely, allowing the gastric contents—both food and stomach acids—to be ejected upward into the esophagus..

[Audio] Conditions that may increase the risk of GERD are pregnancy, hiatal hernia, obesity, and delayed gastric emptying. Several lifestyle factors and certain foods may aggravate symptoms. Smoking, eating large meals, and eating late at night may contribute. Foods known to trigger symptoms include alcohol, fatty foods, caffeine, citric and other acids, gas-producing foods, and certain spices. GERD may cause permanent changes in the tissue lining of the esophagus. These changes have been linked to narrowing of the esophagus and esophageal cancers. Repeated bouts of GERD should not be ignored. Patients diagnosed with GERD are typically advised to stop smoking. To reduce discomfort, patients are advised to remain upright for at least 3 hours after meals. If necessary, patients should sleep with head propped up. Long-term treatment involves reducing the acidity of the stomach contents to limit damage to the esophagus..

[Audio] The way antacids works is implied in their name: they work against acid. These medications react with hydrogen ions in the stomach to neutralize the acid in the stomach. The single-agent antacids available are aluminum hydroxide, calcium carbonate, and magnesium hydroxide. There are multiple combination products available and described in Table 12.2. Antacids are used in the treatment of mild-to-moderate GERD and come in a variety of oral dosage forms. Patients should be advised to shake suspensions well. Side effects include constipation, diarrhea, stomach pain, nausea, and vomiting. Calcium- and aluminum-containing antacids tend to cause constipation, whereas magnesium-containing antacids tend to cause diarrhea. As a class, antacids should be used with caution in renal failure. Calcium-containing products should not be used continuously. Acid hypersecretion may develop when they are used this way, particularly when they are discontinued..

[Audio] The histamine H2 receptor antagonists decrease stomach acidity by binding to H2 receptors on the gastric acid-secreting cells. Cimetidine, famotidine, and nizatidine are the medications in this class. They are available as various oral dosage forms as well as an injectable product. The indication of the H2 receptor antagonists also varies by drug. They are used to treat ulcers, gastric hypersecretory states, GERD, postoperative ulcers, and upper GI bleeds. They are also used to prevent stress ulcers and to relieve heartburn. Drowsiness is a common side effect with cimetidine and nizatidine. Additional side effects vary by agent. The H2 receptor antagonists decrease the absorption of vitamin B12 with prolonged treatment. This could lead to a deficiency of this vitamin. They also decrease the absorption of drugs needing an acidic environment to dissolve..

[Audio] The proton pump inhibitors reduce acid production by blocking the enzyme that pumps hydrogen ions or protons into the stomach. The medications in this class include dexlansoprazole, esomeprazole, lansoprazole, omeprazole, pantoprazole, and rabeprazole. The indication of the proton pump inhibitors varies by drug. As a class, they are used to treat severe erosive esophagitis, GERD, hypersecretory states, H. pylori peptic disease, and heartburn. They are available as various oral dosage forms as well as an injectable product. Headache, nausea, vomiting, and diarrhea are the side effects of this class. Dexlansoprazole and rabeprazole should be used with caution in liver dysfunction. Some pantoprazole formulations contain Polysorbate 80. This can cause hypersensitivity reactions..

[Audio] There is one coating agent on the market: sucralfate. This medication forms a protective coat at the ulcer site that resists degradation by gastric acid as well as pepsin and bile salts. It is used to treat duodenal ulcers and is taken orally. Its main side effect is constipation, and it should be used with caution in renal dysfunction..

[Audio] Misoprostol is the one prostaglandin E1 analog available on the market. It works by replacing the protective prostaglandins inhibited by NSAIDs. Its only indication is the treatment of NSAID-induced gastric ulcers. Its main side effects are diarrhea and abdominal pain. Misoprostol is considered a hazardous agent and should be handled and disposed of appropriately. It should not be used in pregnant individuals due to its potential to cause abortion, birth defects, or premature birth..

[Audio] Chapter 12, Section 3, Peptic Disease and Drug Treatment.

[Audio] An ulcer is a lesion on the surface of an organ or tissue. Peptic ulcers include gastric ulcers which form on the lining of the stomach and duodenal ulcers which form in the lining of the upper part of the duodenum. A stress ulcer usually occurs in patients who are in the intensive care unit and who are under severe physiologic stress from serious illness. These illnesses would include sepsis, burns, major surgery, chronic disease, or chronic infection..

[Audio] Figure 12.5 shows a healthy stomach and an ulcerous stomach. Peptic ulcers are erosions of the mucosal lining of the GI tract. Proton pump inhibitors are commonly used to treat these ulcers..

[Audio] Research has shown that H. pylori, a bacterium, is responsible for the majority of peptic ulcers. A multidrug regimen is prescribed if a patient with peptic ulcer disease has a positive test result for H. pylori. These drug combinations treat the ulcer, reduce symptoms, and kill H. pylori in the GI tract at the same time. All regimens consist of a PPI to heal the ulcer and antibiotics to destroy the bacteria..

[Audio] The combination of bismuth subcitrate potassium, metronidazole, tetracycline plus a PPI is used to treat peptic ulcer disease which is positive for H. pylori. This combination must be used with a PPI in order to be effective. The PPI heals the ulcer while the antibiotics destroy the bacteria. The side effects of this particular combination include nausea, diarrhea, temporary and harmless darkening of the tongue or black stool. This product contains a tetracycline and should not be used in pediatric patients. Additional considerations include its QT-interval prolonging potential. Additionally, bismuth may be neurotoxic. Patients should be monitored for neurotoxicity. The lansoprazole, amoxicillin, clarithromycin combination is also used to treat peptic ulcer disease positive for H. pylori. Its most common side effects are headache, diarrhea, and taste perversion. This combination should be used with caution in older adults and in patients with renal dysfunction..

[Audio] Chapter 12, Section 4, Ulcerative Colitis and Crohn's Disease and Drug Treatments.

[Audio] Ulcerative colitis and Crohn's disease are inflammatory bowel diseases. Both cause chronic diarrhea and their management can be complex. Ulcerative colitis involves excessive inflammation of the GI tract, causing ulcers. The damage tends to be limited to specific portions of the colon or large intestine. Months can go by without symptoms. This is known as remission. When symptoms return, this is known as a flare. Ulcerative colitis can be eliminated through a surgical resection, in which physicians remove the diseased part of the colon. Crohn's disease is similar to ulcerative colitis in that it involves inflammation of the GI tract. However, it is different in that it is an autoimmune disease in which the immune system malfunctions and attacks the tissue lining of the entire GI tract. Although surgery is sometimes performed, it cannot cure Crohn's disease. Symptoms common to both of these disease include diarrhea, vomiting, bloating, fatigue, and abdominal pain..

[Audio] In treating flare-ups of ulcerative colitis or Crohn's disease, corticosteroids are used for their anti-inflammatory and immunosuppressive effects. Oral or rectal dosage forms are used in treating these conditions. Common side effects include headache, dizziness, insomnia, and hunger. Because corticosteroids suppress the immune system, patients taking them are at increased risk of infection. With prolonged use, they have been found to stunt growth in children. A consideration specific to budesonide is that the capsule is to be swallowed whole. It should not be chewed or crushed..

[Audio] Mesalamine and sulfasalazine belong to the class of medications called aminosalicylates. Although it is unclear exactly how these work, they are thought to modulate chemical mediators of the inflammatory response. They are used in the induction and maintenance of remission in patients with Crohn's disease and ulcerative colitis. Both oral and rectal dosage forms are available. The side effects common to both medications are upset stomach, headache, arthralgia, and pharyngitis. There are multiple cautions and considerations which vary by agent..

[Audio] Biologic therapy uses parts of the body's natural immune system to treat a condition or disease. In Crohn's disease and ulcerative colitis, biologic therapy helps stop certain proteins from causing inflammation in the GI tract. Vedolizumab and ustekinumab are both available as IV infusions. Ustekinumab is also available as a subcutaneous injection for maintenance treatment. Side effects for vedolizumab include running nose, headache, nausea, fever, fatigue, respiratory tract infection, cough, bronchitis, itching, and pain. Side effects for ustekinumab include headache, nausea, vomiting, nasopharyngitis, injection site redness and irritation, bronchitis, itching, urinary tract infections, and sinusitis. Both medications carry an increased risk of infection. Patients taking vedolizumab may experience infusion-related reactions..

[Audio] Azathioprine is an immunosuppressant used to induce response and remission in Crohn's disease and ulcerative colitis. It suppresses the immune system by interfering with nucleic acid synthesis. It is only available as a tablet. Side effects specific to azathioprine include arthralgias, rash, alopecia, hepatotoxicity, and increased risk of infection. Azathioprine carries a boxed warning for increased risk of malignancy. Patients should be warned of this risk prior to starting therapy..

[Audio] Chapter 12, Section 5, Gallstones and Drug Treatments.

[Audio] Gallstones are pebble-like structures that obstruct the cystic duct. The cystic duct connects the gallbladder to the common hepatic duct. Classic symptoms of gallstones include intense and dull abdominal discomfort. Other symptoms include sweating, nausea, and vomiting. Figure 12.6 illustrates the gall bladder and the bile duct..

[Audio] Gallstones may be recurrent and are most commonly treated with cholecystectomy, the surgical removal of the gallbladder. However, there are pharmacologic options. Gallstones can be dissolved with gallstone dissolution agents. Ursodiol decreases the cholesterol content of bile and bile stones by reducing the secretion of cholesterol from the liver and reabsorption of cholesterol by the intestines. Its side effects include nausea, diarrhea, constipation, mild stomach pain or discomfort, headache or dizziness. This medication can take months to dissolve gallstones. Patients should be made aware of this so that they expect a longer period of therapy. Ursodiol should be used with caution in liver dysfunction..

[Audio] Chapter 12, Section 6, Diarrhea and Drug Treatments.

[Audio] Diarrhea is defined as excessive, soft, or watery stools. Excessive stool can mean large stool volume or larger number of bowel movements than normal. Acute diarrhea is a common condition that can be caused by infections such as traveler's diarrhea and food poisoning. In addition, certain drugs, can cause acute diarrhea. Chronic diarrhea is less common and can be caused by irritable bowel syndrome, ulcerative colitis, or Crohn's disease. Diarrhea can lead to dangerous complications. It can quickly lead to dehydration. Because diarrhea decreases GI transit time, it will impair absorption of drugs, vitamins, nutrients, and toxins..

[Audio] Adsorbents are a class of antidiarrheals that are used to slow or stop loose stools. They are thought to work by binding to diarrhea-causing toxins preventing them from adhering to the walls of the GI tract. In addition to its adsorbent action, bismuth subsalicylate also has antisecretory and anti-inflammatory effects. It is used to treat diarrhea, H. pylori infection, and traveler's diarrhea. It is given orally and its side effects include constipation, nausea, vomiting, and darkening of the tongue and/or stools. Bismuth subsalicylate has been rarely associated with tinnitus, confusion, and weakness. When using this agent, a harmless, temporary darkening of tongue and stools may occur. It should be used cautiously in renal failure or gout. Children and adolescents are at risk of a condition known as Reye's syndrome, a potentially life-threatening disorder caused by salicylate use for viral infections..

[Audio] Antimotility drugs for diarrhea work by slowing peristalsis, the smooth muscle contractions that propel fecal matter along the colon. Water absorption from the feces is increased as the colon contents spend more time in GI transit. Most of these drugs contain opiates and, therefore, are controlled substances. Long-term use of narcotics for pain leads to constipation. The use of narcotics to control diarrhea is an example of using a drug for its side effects to treat another condition. The combination of diphenoxylate and atropine is given orally for diarrhea. Side effects to be aware of include dry mouth, blurred vision, flushing, urinary retention, constipation, paralytic ileus, respiratory depression, and sedation. Because diphenoxylate can cross the blood-brain barrier, there is the potential for euphoria with this product. Because of its controlled substance status, there are restrictions associated with its purchase. A physician should be consulted for fever, bloody stool, or if diarrhea is still present after 48 hours of use. Patients should exercise caution regarding this product's effect on driving ability..

[Audio] Antimotility drugs for diarrhea work by slowing peristalsis, the smooth muscle contractions that propel fecal matter along the colon. Water absorption from the feces is increased as the colon contents spend more time in GI transit. Most of these drugs contain opiates and, therefore, are controlled substances. Long-term use of narcotics for pain leads to constipation; the use of narcotics to control diarrhea is an example of using a drug for its side effects to treat another condition. The combination of difenoxin and atropine has the identical mechanism, uses, and side effects as diphenoxylate / atropine. There is a potential for CNS depression and it should be used with caution in liver disease. Loperamide also has the identical mechanism and indications as diphenoxylate / atropine. Its side effects include drowsiness, constipation, and dry mouth. Loperamide does not act on the CNS so the cautions regarding euphoria and CNS depression are not present. It should be discontinued if diarrhea lasts longer than two days, symptoms worsen, or abdominal swelling or bulging develops..

[Audio] Giardia lamblia is a protozoan acquired through water, food, or person-to-person contact. Symptoms of giardiasis include abdominal cramps, bloating, nausea, and watery diarrhea. Nitazoxanide interferes with a process necessary for anaerobic energy metabolism. It is indicated for infectious diarrhea caused by G. lamblia and Cryptosporidium parvum. It is taken orally and its side effects include headache, abdominal pain, nausea, and urine discoloration. Nitazoxanide should be used with caution in renal or hepatic dysfunction. Its safety has not been established in patients with HIV. Patients with diabetes should be made aware that this drug contains 1.48 grams of sucrose per 5 milliliters. Rifaximin is a medication which inhibits RNA synthesis and is used for traveler's diarrhea. Traveler's diarrhea poses a risk when traveling to some foreign countries. It is acquired through food or water contaminated with E. coli. Preventive measures include eating well-cooked foods, peeling fruits and vegetables, and drinking bottled water. The main side effect of rifaximin is flatulence. Hypersensitivity reactions may develop and bacterial superinfection may develop with prolonged use. This medication is not effective for systemic infections as it is not absorbed into the body..

[Audio] Chapter 12, Section 7, Constipation and Flatulence and Drug Treatments.

[Audio] Constipation is the opposite of diarrhea. It is characterized by infrequent bowel movements, small stool size, hard stools, or the feeling of incomplete bowel evacuation. Many episodes of constipation are related to a diet low in fiber or fluid intake. Constipation can also be caused by certain foods or drugs. Although many drugs have the potential to cause diarrhea or constipation, the ones most associated with constipation include antacids and pain medications such as opiates. Stress may also exacerbate constipation, whereas light exercise promotes GI motility. Dietary modification and lifestyle changes should accompany pharmacologic treatment of constipation. Patients with repeat bouts of constipation should drink plenty of fluids, eat adequate fiber, and exercise regularly..

[Audio] Fiber is defined as the undigested residue of fruits, vegetables, and other foods of plant origin. It is classified as soluble or insoluble. Soluble fiber is made of carbohydrates that dissolve in water. Examples include beans, peas, fruits, and oats. Insoluble fiber comes from plant cell walls that cannot dissolve in water. Examples of foods that contain this type of fiber include rye, wheat, and other grains. Fiber increases the forward motion in the colon. Chronic constipation has been associated with low-fiber diets..

[Audio] The bulk-forming laxatives include methylcellulose, polycarbophil, and wheat dextrin. They remain in the GI tract, drawing water and electrolytes into the GI system. This triggers peristalsis and facilitates bowel movements. They are used orally for the prevention of constipation. They rarely cause obstruction of the esophagus. The bulk-forming laxatives should be used with caution in esophageal strictures, ulcers, intestinal adhesions, and patients with difficulty swallowing. They should be taken with at least 8 ounces of liquid..

[Audio] The main stool softener or surfactant laxative available is docusate. It's available in oral dosage forms as well as an enema. Docusate acts as a detergent, helping the fatty and watery components of the intestinal contents to mix, making the stool soft and mushy. Its side effects include throat irritation, abdominal pain, diarrhea, and intestinal obstruction. The liquid form of this medication should be taken with 8 ounces of juice or milk to mask its bad taste. Patients should be advised to drink plenty of fluids to enhance its effect. Electrolyte imbalance may develop from excessive or long-term use..

[Audio] Osmotic laxatives such as glycerin stimulate evacuation of the lower bowel by drawing water into the colon. Glycerin suppositories offer quick relief of constipation. Lactulose reduces the absorption of ammonia and empties the bowel. It is used orally to prevent and treat hepatic-induced encephalopathy. Lactulose use is associated with nausea and vomiting, cramps, diarrhea, and anorexia. Its use can lead to electrolyte abnormalities and it should be used with caution in diabetes..

[Audio] Additional osmotic laxatives include polyethylene glycol 33 50 and magnesium hydroxide. Polyethylene glycol 33 50 is taken daily to maintain to prevent constipation by softening stool and is available as a powder for oral solution. The side effects of this medication are nausea, diarrhea, bloating, and flatulence. It should be avoided in bowel obstruction and used with caution in kidney dysfunction. Magnesium hydroxide causes retention of fluid, which distends the colon and increases GI smooth muscle contractions. It is used as both a laxative and antacid and is available in oral dosage forms. It side effects are the same as those of polyethylene glycol 33 50. Magnesium hydroxide should be used with caution in patients with kidney dysfunction, cardiac disease, and pre-existing electrolyte abnormalities..

[Audio] Bisacodyl and senna are stimulant laxatives. They stimulate parasympathetic neurons that control bowel muscles, thereby enhancing peristalsis and GI motility. They are given with long-term narcotic pain medications, which can cause constipation. Their side effects include mild abdominal pain, nausea, vomiting, and rectal burning. To achieve the best effect, bisacodyl should be taken with a full glass of water on an empty stomach..

[Audio] Lubiprostone is an agent that activates chloride channels locally in the small intestine, which increases intestinal fluid secretion. It is indicated in chronic idiopathic constipation, opioid-induced constipation, and irritable bowel syndrome with constipation. Nausea is the main side effect. Lubiprostone may cause dyspnea and chest tightness. It should be used with caution in moderate-to-severe liver dysfunction..

[Audio] Flatulence is stomach or intestinal gas and affects many patients. Intestinal gas is typically caused by the fermentation of undigested food in the colon, intestinal bacteria changes when taking antibiotics or other medications, poor carbohydrate absorption, swallowed air, and constipation. In addition, certain foods such as cauliflower, cabbage, and broccoli can cause flatulence. Simethicone is an antiflatulent agent that causes gas bubbles to break or to coalesce into a foam that can be eliminated more easily by belching or passing flatus. It is taken to relieve flatulence, functional gastric bloating, and postoperative gas pains. It's a well tolerated medication that is taken orally. Some of its dosage forms contain benzyl alcohol and should not be used by pediatric patients..

[Audio] Bowel evacuants are used to cleanse the bowel prior to a GI procedure such as a colonoscopy or X-ray with barium enema. Polyethylene glycol 33 50 with electrolytes work by increasing the osmolarity of bowel contents, drawing large amounts of water into the lumen to flush bowel contents out. Abdominal distention, anal discomfort, nausea, abdominal pain, and vomiting are its expected side effects. Serious cardiac arrythmias can develop with this agent. In addition, it should be used with caution in renal dysfunction. Sodium phosphate works by drawing water into the colon. It has been associated with less nausea, vomiting, and bloating than other bowel preparation products. Sodium phosphate carries a boxed warning for the development of acute phosphate nephropathy..

[Audio] Chapter 12, Section 8, Other Gastrointestinal Diseases That May Accompany Constipation and Drug Treatments.

[Audio] Low amounts of fiber in the diet not only produce a state of constipation; they can also increase the likelihood that a patient will encounter a number of other GI diseases. Several of these diseases are discussed here. Diverticular disease occurs when an out-pocketing from the bowel wall forms and/or becomes inflamed. It is believed to results form a deficiency of fiber over time. Hiatal hernia is a protrusion through the esophageal hiatus of the diaphragm. It is related to chronic constipation. Straining to pass small, firm stools can raise intra-abdominal pressure. Irritable bowel syndrome results from insufficient tone or spasticity of the lower GI tract to regulate bowel activity..

[Audio] Hemorrhoids result from pressure exerted on anal veins while straining to pass stool. This causes engorgement of the local vasculature, leading to hemorrhoidal bleeding when passing a small, hard stool. The most commonly used hemorrhoidal agents are hydrocortisone and nitroglycerin. Hydrocortisone treats inflammation. Nitroglycerin causes smooth muscle relaxation, thus reducing resting pressure on the anal canal and allowing healing of a tear or fissure in the anal canal..

[Audio] Chapter 12, Section 9, Nausea and Vomiting and Drug Treatments.

[Audio] Vomiting is also referred to as emesis. It can be initiated in two ways: by stimulation of the brain's chemoreceptor trigger zone or by stimulation of the stomach's vagal receptors. The CTZ receives input from two areas of the brain and from blood-borne stimuli such as bacterial toxins and drugs. Emesis often results from narcotic intake and is dose related. Vomiting can lead to complications such as dehydration, electrolyte imbalance leading to alkalosis or arrhythmias, and aspiration pneumonia..

[Audio] An antiemetic is a drug that prevents vomiting. It works primarily in the vomiting center to inhibit impulses that travel to the stomach. The antihistamines and anticholinergics include diphenhydramine, dimenhydrinate, meclizine, and scopolamine. These work by blocking histamine and acetylcholine, neurotransmitters in the CTZ and vomiting center. They are used for motion sickness and are available as injection, topical patch, and several oral dosage forms. The main side effects for this class of drugs are drowsiness, dry mouth, urinary retention, and paradoxical excitement in children. Paradoxical excitement means that, instead of causing drowsiness, these medications may cause excitement. These drugs should be used cautiously in patients with high blood pressure or heart problems..

[Audio] Dolasetron, granisetron, and ondansetron are serotonin receptor antagonists. As the name suggests, these drugs work by blocking serotonin receptors in the brain and GI tract. This stops nausea signals traveling from the brain to the stomach. Serotonin receptor antagonists are used to prevent and treat severe nausea and vomiting associated with chemotherapeutic medications, radiation treatment, or anesthesia. They are available as injection, topical patch, and oral dosage forms. The main side effects associated with this medication class include headache, constipation, drowsiness, and fatigue. Due to the potential for these medications causing drowsiness, patients should be reminded that activities such as driving may not be safe while taking them..

[Audio] The dopamine receptor antagonists include prochlorperazine, promethazine, and metoclopramide. They block dopamine receptors and inhibit the CTZ. They are available as injection, suppository, and oral dosage forms. The side effect common to the drugs in this class is drowsiness. Additional side effects vary by agent. Movement disorders such as tardive dyskinesia and dystonia are possible with dopamine receptor antagonists, particularly at high doses. These are called extrapyramidal side effects. Such effects include uncontrollable movements of the eyes, face, and limbs that may become permanent. Patients, especially older adults, have to be closely monitored for the appearance of EPS effects. If EPS effects appear, patients should stop taking the antiemetic. Important considerations in the use of this class vary by agent. Prochlorperazine should be used with caution in liver problems while promethazine should not be used in children less than 2 years old. Metoclopramide carries the risk of tardive dyskinesia..

[Audio] The neurokinin-1 receptor antagonists prevent nausea by blocking neurokinin receptors. This is the preferred binding side for substance P, a neuropeptide involved in the induction of nausea and vomiting. Aprepitant is an oral medication. Fosaprepitant is the injectable form of Emend. They are both used to prevent postoperative and chemotherapy-related nausea. Common side effects include fatigue, muscle weakness, and constipation. These drugs should be used with caution in renal impairment..

[Audio] Chapter 12, Section 10, Hepatitis and Drug Treatments.

[Audio] Hepatitis is a liver disease which can damage liver cells and cause the liver to become swollen and tender. There are multiple forms of hepatitis. All are caused by viruses but differ in the way they are transmitted. Hepatitis A is transmitted through blood and body fluids. It is treated with supportive care such as food and rest. Hepatitis A can be prevented by vaccination. If patients know they have been exposed, they can be protected with immune globulin if it's within 2 weeks of exposure. Immune globluin provides passive immunity to the disease..

[Audio] Hepatitis B is transmitted through body fluids, sexual contact, and perinatally. There are two forms: acute and chronic. Acute hepatitis B clears up on its own while chronic hepatitis B is treated with antivirals. Chronic hepatitis B can lead to cirrhosis or liver cancer. Hepatitis B is prevented through vaccination. Most healthcare workers, including pharmacy technicians, should receive vaccines for hepatitis B. Hepatitis C is transmitted through blood transfusions or illicit drug use. It is classified by type according to virus genotype. Chronic hepatitis C can lead to fibrosis and end-stage liver disease. It is important to treat the acute form to prevent progression to the chronic..

[Audio] Entecavir is given orally for the treatment of hepatitis B. Its side effects include headache, fatigue, dizziness, and nausea. Entecavir carries three boxed warnings. The first is for lactic acidosis, severe liver enlargement, and fatty liver. The second warns of the potential for severe hepatitis B exacerbation upon discontinuation. The third boxed warning is for HIV resistance to some antiretrovirals if entecavir is used in patients with unrecognized or untreated HIV. Lamivudine is used orally for the treatment of hepatitis B and HIV. Its side effects include headache, nausea, malaise and fatigue, nasal symptoms, diarrhea, and cough. Lamivudine carries three boxed warnings. The first is that Epivir-HBV is not to be used for HIV. The second warns of the potential for severe hepatitis B exacerbation upon discontinuation. The third boxed warning is for HIV resistance to lamivudine if used in patients with undiagnosed HIV..

[Audio] Peginterferon alfa-2a is an injectable medication used to treat hepatitis C and chronic hepatitis B. Fatigue, headache, myalgia, and fever are its main side effects. It has a boxed warning for causing or aggravating fatal or life-threatening neuropsychiatric, autoimmune, ischemic, and infectious disorders. Therapy should be discontinued immediately if patients develop symptoms of these disorders. Ribavirin is used in the treatment of hepatitis C and respiratory syncytial virus. It is given orally for hepatitis C. Ribavirin is known to cause bothersome side effects, including anxiety, emotional lability, irritability, fatigue, fever, headache, injection-site reaction, myalgia, nausea, and rigor. Ribavirin has several boxed warnings. The first warning is that monotherapy is ineffective for chronic hepatitis C. It should always be used with other therapies. The second warning is for the risk of hemolytic anemia. The third boxed warning is that ribavirin can cause severe teratogenic and embryocidal effects. It should not be used in individuals who are pregnant or whose partners are pregnant..

[Audio] The combination product of ledipasvir and sofosbuvir is used orally in the treatment of hepatitis C. Common adverse reactions to both drugs are fatigue and headache. Significant drug interactions may exist, and screening should occur prior to starting either drug. The ledipasvir and sofosbuvir combination product may contain lactose. Use with caution in patients with lactose intolerance. Tenofovir is available orally to treat hepatitis B and HIV. Its main side effects are dizziness, depression, skin rash, and dyslipidemia. Tenofovir carries two boxed warnings. The first is for the risk of lactic acidosis and severe hepatomegaly. The second is for the risk of severe and acute exacerbation of hepatitis B upon discontinuation. Kidney toxicity is also a concern with this medication..

[Audio] Elbasvir and grazoprevier are two drugs used in combination to treatment chronic hepatitis C genotypes 1 or 4. It is available as an oral combination product with the most common side effects being fatigue, headache, and nausea. This product carries a boxed warning for reactivation of hepatitis B infection. In addition, liver toxicity is a concern with use. Glecaprevir and pibrentasvir are two drugs used in combination to treat chronic hepatitis C genotypes 1 through 6. It is available as an oral combination product. The most commonly reported side effects include headache and fatigue. Similar to elbasvir and grazoprevier, this product also carries a boxed warning for reactivation of hepatitis B infection and concerns for liver toxicity..

[Audio] The combination of ombitasvir, paritaprevir, ritonavir, and dasabuvir is used orally in the treatment of chronic hepatitis C. Its most common side effects are fatigue, nausea, itching, insomnia, and weakness. An elevation of hepatic enzymes may occur with this product, particularly with the use of ethinyl estradiol. HIV resistance to ritonavir may occur in patients with undiagnosed or untreated HIV. This product should be used with caution in liver impairment. Simeprevir is used orally for the treatment of chronic hepatitis C. It is not meant for monotherapy and must be used in combination with other products. Common adverse effects include rash and photosensitivity. Simeprevir doses should not be missed. This may lead to viral resistance. It should not be used in patients with moderate-to-severe hepatic dysfunction..

[Audio] The combination of sofosbuvir and velpatasvir is used in the treatment of all types of chronic hepatitis C. It is taken orally. Its common side effects are headache and fatigue. This product has a boxed warning for reactivation of hepatitis B infection..

[Audio] Chapter 12, Section 11, Complementary and Alternative Therapies.

[Audio] Shiatsu acupressure or massage has been used to treat nausea. Shiatsu acupressure involves finger pressure at certain points along the body. Ginger is used to reduce nausea associated with surgery, vertigo, and motion sickness. Its side effects include heartburn, gas, bloating, mouth and throat irritation, and diarrhea..

[Audio] Probiotics are products that contain live cultures of yeast or bacteria. They are used for diarrhea, constipation, H. pylori infection, and antibiotic-induced diarrhea. They work by competing with and replacing or displacing harmful bacteria. Aloe, shown on the right, ingested orally may be used to treat patients with constipation. It appears to work as a stimulant laxative. Caution is advised when taking aloe supplements, as adverse effects, including diarrhea and drug interactions, are possible..