Chapter 50: Acid-Controlling Drugs (PDF)

Chapter 50 Acid- Controlling Drugs KR by Katie Robinson Cells of the Gastric Gland 1 Parietal Cells 2 Chief Cells These cells produce and Chief cells produce and secrete hydrochloric acid secrete pepsinogen, a (HCl), which plays a cr...

Chapter 50 Acid- Controlling Drugs KR by Katie Robinson Cells of the Gastric Gland 1 Parietal Cells 2 Chief Cells These cells produce and Chief cells produce and secrete hydrochloric acid secrete pepsinogen, a (HCl), which plays a crucial precursor to pepsin, an role in the digestive process. enzyme that digests proteins. 3 Mucous Cells 4 Endocrine and Enterochromaffin Cells Mucous cells secrete mucus, which helps protect the Endocrine cells secrete stomach lining from the hormones such as gastrin, acidic environment. which stimulate acid production, while enterochromaffin cells secrete histamine, another stimulator of HCl production. Hydrochloric Acid Parietal Cell Secretion Digestive Function Antimicrobial Defense Parietal cells in the gastric glands HCl helps digest food by HCl is essential for the stomach's secrete hydrochloric acid (HCl), a activating pepsinogen, a defense against pathogens, strong acid. precursor to the digestive enzyme preventing infections in the pepsin. gastrointestinal tract. Acid-Related Diseases Peptic ulcer disease (PUD) is a condition characterized by sores in the lining of the stomach or duodenum. The digestive enzyme pepsin breaks down the gastrointestinal (GI) mucosa in PUD. The bacterium Helicobacter pylori (H. pylori) is implicated in the development of PUD. This bacteria colonizes the GI tract in a majority of patients with PUD. First-line therapy for PUD consists of a 10- to 14-day course of a proton pump inhibitor (PPI), clarithromycin, and amoxicillin. Acid-Related Diseases (Cont.) Stress-Related Factors Mucosal Damage Common factors include Stress-related mucosal decreased blood flow, damage is common in mucosal ischemia, critical care. hypoperfusion, and reperfusion injury. Predisposing Factors Prophylaxis Nasogastric tubes and Stress ulcer prophylaxis is ventilators are not recommended after predisposing factors to GI the patient is no longer in bleeding. the ICU. Antacids Neutralize Acid Salts Antiflatulents Antacids are basic compounds Commonly composed of salts like Some antacid preparations that directly neutralize stomach aluminum, magnesium, calcium, include simethicone, which acid. and sodium. reduces gas buildup. Antacids: Mechanism of Action Acid Neutralization Gastric Mucosal Defense Antacids do not prevent the overproduction of acid. Antacids promote gastric mucosal defense mechanisms. They neutralize existing acid secretions in the stomach. They increase the production of protective substances. Mucus Bicarbonate Prostaglandins Antacids: Drug Effects Pain Reduction Mechanism of Action Antacids reduce pain associated with acid-related Reduced acidity lessens pain by inhibiting the disorders by neutralizing stomach acid. protein-digesting ability of pepsin. Raising the gastric pH by 1 point neutralizes 90% of Antacids also increase the resistance of the the gastric acid. stomach lining to irritation and increase the tone of the cardiac sphincter. Antacids: Contraindications Antacids are contraindicated in patients with severe renal failure or electrolyte disturbances because of the potential for toxic accumulation of electrolytes. Antacids can also worsen gastrointestinal obstruction as they may stimulate motility when undesirable. Antacids: Aluminum Salts Constipation Renal Disease Aluminum salts can cause constipation. Aluminum salts are often recommended for patients with renal disease because they are more easily excreted. Antacids: Magnesium Salts Magnesium salts are commonly used in antacid formulations. They are effective in neutralizing stomach acid and can also help to relieve constipation. However, magnesium salts can cause diarrhea. It is important to be aware of the potential for magnesium salts to cause diarrhea. Magnesium is absorbed from the gastrointestinal tract and is excreted by the kidneys. In patients with renal failure, the kidneys are unable to excrete excess magnesium, which can lead to magnesium toxicity. Magnesium toxicity can cause a variety of symptoms, including muscle weakness, nausea, vomiting, and coma. Magnesium salts should be used with caution in patients with renal failure. The dosage of magnesium salts should be adjusted according to the patient's renal function. Antacids: Calcium Salts 1 1. Forms 2 2. Side Effects Calcium carbonate is Calcium salt antacids the most common form may cause constipation of calcium salt and kidney stones. antacids. 3 3. Renal Disease 4 4. Hyperacidity Rebound Calcium salts are not recommended for Calcium salt antacids patients with renal may increase gastric disease. acid secretion. Antacids and Antiflatulents Antiflatulents Simethicone Antiflatulents are used to Simethicone (Mylicon) is a relieve the painful common antiflatulent that symptoms associated with helps to break up gas gas. bubbles in the gastrointestinal tract. Mechanism of Action Simethicone works by reducing the surface tension of gas bubbles, allowing them to be more easily released. Antacids: Adverse Effects Constipation Diarrhea Kidney Stones Aluminum and calcium salts can Magnesium salts are known to Calcium salts may increase the cause constipation, especially cause diarrhea, potentially risk of kidney stone formation, when used in high doses or for leading to dehydration. particularly in individuals with a extended periods. predisposition. Histamine 2 (H2) Receptor Antagonists Mechanism of Action Drug Effects H2 receptor antagonists H2 receptor antagonists block the action of are effective in treating histamine at the H2 peptic ulcers, receptors located in the gastroesophageal reflux parietal cells of the disease (GERD), and stomach. This reduces Zollinger-Ellison gastric acid secretion. syndrome. Common H2 Antagonists Some common H2 antagonists include cimetidine (Tagamet), nizatidine (Axid), famotidine (Pepcid), and ranitidine (Zantac). H2 Antagonists: Mechanism of Action H2 Receptor Blockade Reduced Hydrogen Ion Increased Stomach pH Secretion H2 antagonists competitively Decreased gastric acid production block the H2 receptor on acid- Blocking the H2 receptor reduces leads to an increase in the pH of producing parietal cells in the the secretion of hydrogen ions the stomach, making it less stomach. (H+) from parietal cells, acidic. decreasing gastric acid production. H2 Antagonists: Drug Effect and Indications Drug Effect Indications H2 antagonists reduce These drugs are the secretion of gastric indicated for the acid by blocking the H2 treatment of various receptors on parietal conditions associated cells. with excess gastric acid production, such as GERD, PUD, and Zollinger-Ellison syndrome. Additional Uses H2 antagonists can be used to treat erosive esophagitis and as adjunct therapy for upper GI bleeding. H2 Antagonists: Adverse Effects Common Adverse Adverse Effects Drug Interactions Central Nervous Effects (Cont.) System Effects H2 antagonists can H2 antagonists are Cimetidine may cause interact with other In some cases, generally well- impotence and medications, including especially in elderly tolerated. They are gynecomastia. These antifungals. Cimetidine patients, H2 often prescribed for side effects are rare in particular can antagonists can lead to long-term use, with few and tend to resolve decrease the central nervous system adverse effects. after discontinuing the effectiveness of adverse effects. These However, certain medication. antifungals, which may include confusion, medications can have affect their therapeutic disorientation, and unexpected side action. altered mental status. effects. H2 Antagonists: Drug Interactions P-450 System Cimetidine can inhibit the P-450 system, leading to increased levels of other drugs. Drug Absorption H2 antagonists may interfere with the absorption of drugs requiring an acidic GI environment. Cimetidine Use Cimetidine's potential for interactions has led to a decline in its use. H2 Antagonists: Drug Interactions (Cont.) Smoking can decrease the effectiveness of H2 blockers. This is likely due to the nicotine in cigarettes, which can increase the production of gastric acid. The increased acid production can overcome the effects of H2 blockers, leading to less effective symptom relief. For optimal results, H2 receptor antagonists are taken 1 to 2 hours before antacids. This allows the H2 blockers to work more effectively by reducing the production of gastric acid. Antacids, on the other hand, work by neutralizing the acid that is already present in the stomach. By taking the H2 blockers before the antacids, you can ensure that the antacids are working on a smaller amount of acid, and therefore will be more effective. Proton Pump Inhibitors Proton pump inhibitors (PPIs) are a class of drugs that block the production of stomach acid. Parietal cells in the stomach release hydrogen ions (protons) during the process of hydrochloric acid production. The proton pump is a key component in this process. PPIs are more effective than H2 blockers and antihistamines because they directly inhibit the proton pump, unlike the other medications. Proton Pump Inhibitors: Mechanism of Action Irreversible Binding Achlorhydria Proton pump inhibitors (PPIs) irreversibly bind to the The result of PPI action is achlorhydria, where all H+/K+ ATPase enzyme. gastric acid secretion is temporarily blocked. This binding prevents the movement of hydrogen For normal acid secretion to resume, the parietal ions from the parietal cell into the stomach. cell must synthesize new H+/K+ ATPase. Proton Pump Inhibitors: Indications 1 1. Gastroesophageal Reflux Disease (GERD) 2 2. Erosive Esophagitis Proton pump inhibitors (PPIs) are commonly PPIs are used to treat erosive esophagitis, a prescribed for long-term management of more serious condition that involves GERD. They effectively reduce acid production inflammation and damage to the esophageal in the stomach, alleviating symptoms like lining. PPIs help heal the damaged tissue and heartburn and acid reflux. prevent further damage. 3 3. Duodenal and Gastric Ulcers 4 4. Nonsteroidal Anti-inflammatory Drug (NSAID)-Induced Ulcers PPIs are prescribed for short-term treatment of active duodenal ulcers and benign gastric NSAIDs can increase the risk of developing ulcers. They help promote ulcer healing and ulcers. PPIs can be used to prevent or treat prevent recurrence. NSAID-induced ulcers, especially in individuals with risk factors for ulcer development. Proton Pump Inhibitors: Adverse Effects GI Infections Osteoporosis Possible increased risk of _Clostridium Long-term PPI use is associated with a higher difficile_ infections, which can cause severe risk of osteoporosis, potentially leading to diarrhea. fractures. Pneumonia Magnesium Depletion PPIs may increase the risk of pneumonia, Long-term PPI use may lead to magnesium particularly in hospitalized patients and the depletion, causing fatigue, muscle weakness, elderly. and other complications. Proton pump inhibitors (PPIs) are generally well tolerated. However, long-term use may mask serious stomach issues and may have potential risks, such as increased susceptibility to GI infections, osteoporosis, pneumonia, and magnesium depletion. Sucralfate (Carafate) Sucralfate is a cytoprotective drug used to treat stress ulcers and peptic ulcer disease. It binds to the base of ulcers and erosions, forming a protective barrier over these areas. This barrier protects the ulcer from pepsin, which normally breaks down proteins, worsening ulcer symptoms. Misoprostol (Cytotec) Prostaglandin E Analog Cytoprotective Activity Misoprostol is a synthetic Misoprostol promotes local prostaglandin E analog cell regeneration and helps that works by enhancing to maintain mucosal blood the production of mucus flow, ultimately protecting and bicarbonate in the the stomach lining from stomach, thus protecting damage caused by NSAID the gastric mucosa from medications. injury. NSAID-Induced Gastric Ulcers Misoprostol is primarily used for the prevention of gastric ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDS), which can cause inflammation and damage to the stomach lining. Simethicone (Mylicon) Simethicone is an antiflatulent drug. Simethicone helps reduce discomfort caused by gastric or intestinal gas (flatulence). Simethicone alters the elasticity of gas bubbles coated in mucus, breaking them into smaller bubbles. This decrease in gas pain and increases gas expulsion via the mouth or rectum. Nursing Implications: Antacids (Cont.) Chewable Tablets Liquid Forms Administer with Water Be sure that chewable tablets are Liquid forms should be shaken Administer with at least 8 oz of chewed thoroughly before giving. well before administering. water to enhance absorption. Long-term self-medication with antacids may mask symptoms of serious underlying diseases, such as malignancy or bleeding ulcers. If symptoms remain ongoing, the patient should seek medical evaluation. Nursing Implications: Antacids (Cont.) Monitoring for Adverse Effects Monitoring for Therapeutic Response Nausea, vomiting, abdominal pain, and diarrhea are Regularly assess patients for symptom relief and common adverse effects associated with antacid improvement in their condition. Monitor for signs of use. These symptoms can be more pronounced in improvement, such as decreased pain, reduced patients with pre-existing gastrointestinal heartburn, and a reduction in the frequency of acid conditions. reflux episodes. Calcium-containing antacids can also lead to If symptoms persist or worsen despite antacid constipation and acid rebound, a phenomenon therapy, promptly notify the healthcare provider for where gastric acid production increases after the further evaluation and potential adjustments to the antacid effect wears off. treatment plan. Nursing Implications: H2 Antagonists Patient Assessment Special Populations Assess patients for Use with caution in allergies to H2 confused or disoriented antagonists. Evaluate patients and elderly renal and liver function. patients. Drug Interactions Intravenous Administration Administer H2 antagonists 1 to 2 hours before Follow specific antacids to optimize administration guidelines effectiveness. for intravenous doses. Nursing Implications: Proton Pump Inhibitors 1 1. Allergies 2 2. Liver Disease Assess for allergies to Assess for a history of proton pump inhibitors. liver disease. 3 3. Parenteral 4 4. Drug Interactions Administration Proton pump inhibitors Not all proton pump may increase serum inhibitors are available levels of diazepam and for parenteral phenytoin. administration.