Acid- Controlling Drugs- Chapter 50.pptx

Chapter 50 Acid-Controlling Drugs  Acid-Related Pathophysiology  The stomach secretes  Hydrochloric acid (HCl)  Bicarbonate  Pepsinogen  Intrinsic factor  Mucus  Prostaglandins 2  Glands of t...

Chapter 50 Acid-Controlling Drugs  Acid-Related Pathophysiology  The stomach secretes  Hydrochloric acid (HCl)  Bicarbonate  Pepsinogen  Intrinsic factor  Mucus  Prostaglandins 2  Glands of the Stomach  Cardiac  Pyloric  Gastric  The cells of the gastric gland are the largest in number and of primary importance when discussing acid control. 3  Cells of the Gastric Gland  Parietal  Chief  Mucous 4  Cells of the Gastric Gland (Cont.)  Parietal cells  Produce and secrete HCl  Primary site of action for many of the drugs used to treat acid-related disorders 5  Cells of the Gastric Gland (Cont.)  Chief cells  Secrete pepsinogen, a proenzyme  Pepsinogen becomes pepsin when activated by exposure to acid.  Pepsin breaks down proteins (proteolytic). 6  Cells of the Gastric Gland (Cont.)  Mucous cells  Mucus-secreting cells (surface epithelial cells)  Provide a protective mucus coat  Protect against self-digestion by HCl and digestive enzymes 7  Hydrochloric Acid  Secreted by parietal cells when stimulated by food, caffeine, chocolate, and alcohol  Maintains stomach at pH of 1 to 4  Acidity aids in the proper digestion of food and defenses against microbial infection via the gastrointestinal (GI) tract.  Secretion also stimulated by:  Large fatty meals  Emotional stress 8  Acid-Related Diseases  Peptic ulcer disease (PUD)  Gastric or duodenal ulcers that involve digestion of the GI mucosa by the enzyme pepsin  Helicobacter pylori (H. pylori)  Bacterium found in GI tract of 90% of patients with duodenal ulcers and 70% of those with gastric ulcers  First-line therapy includes a 10- to 14-day course of a proton pump inhibitor (PPI) and the antibiotics clarithromycin and either amoxicillin or metronidazole or a combination of a PPI, bismuth subsalicylate, and the antibiotics tetracycline and metronidazole. 9  Acid-Related Diseases (Cont.)  Stress-related mucosal damage  GI lesions are a common finding in intensive care unit (ICU) patients, especially within the first 24 hours after admission.  Factors include decreased blood flow, mucosal ischemia, hypoperfusion, and reperfusion injury.  Nasogastric (NG) tubes and ventilators predispose patients to GI bleeding.  A histamine receptor–blocking drug or a PPI are given for prevention.  Data do not support the continued use of stress ulcer prophylaxis after the patient is no longer in the ICU. 10 Types of Acid-Controlling Drugs  Antacids  H2 antagonists  PPIs 11  Antacids  Basic compounds used to neutralize stomach acid  Salts of aluminum, magnesium, calcium, and/or sodium  Many antacid preparations also contain the antiflatulent (antigas) drug simethicone.  Many aluminum- and calcium-based formulations also include magnesium, which not only contributes to the acid-neutralizing capacity but also counteracts the constipating effects of aluminum and calcium. 12  Antacids (Cont.)  Calcium antacids may lead to the development of kidney stones and increased gastric acid secretion.  Antacids containing magnesium must be avoided in patients with renal failure.  Sodium bicarbonate is a highly soluble antacid form with a quick onset but short duration of action. 13  Antacids: Mechanism of Action  Do not prevent the overproduction of acid but instead help to neutralize acid secretions  Promote gastric mucosal defense mechanisms  Stimulate secretion of:  Mucus: protective barrier against HCl  Bicarbonate: helps buffer acidic properties of HCl  Prostaglandins: prevent activation of proton pump 14  Antacids: Drug Effects  Reduction of pain associated with acid-related disorders  Raising the gastric pH 1 point (1.3 to 2.3) neutralizes 90% of the gastric acid.  Reducing acidity reduces pain as a result of: Base-mediated inhibition of the protein-digesting ability of pepsin Increase in the resistance of the stomach lining to irritation Increase in the tone of the cardiac sphincter 15  Antacids: Indications  Acute relief of symptoms associated with peptic ulcer, gastritis, gastric hyperacidity, and heartburn 16  Antacids: Contraindications  Known allergy to a specific drug product  Severe renal failure or electrolyte disturbances: potential toxic accumulation of electrolytes in the antacids themselves  GI obstruction: antacids may stimulate GI motility when they are undesirable because of the presence of an obstructive process requiring surgical intervention 17  Antacids  Over-the-counter (OTC) formulations available as:  Capsules and tablets  Powders  Chewable tablets  Suspensions  Effervescent granules and tablets 18  Antacids (Cont.)  Used alone or in combination  Aluminum salts  Magnesium salts  Calcium salts  Sodium bicarbonate 19  Antacids: Aluminum Salts  Have constipating effects  Often used with magnesium to counteract constipation  Often recommended for patients with renal disease (more easily excreted)  Examples  Aluminum carbonate: Basaljel  Hydroxide salt: AlternaGEL  Combination products (aluminum and magnesium): Gaviscon, Maalox, Mylanta, Di-Gel 20  Antacids: Magnesium Salts  Commonly cause diarrhea; usually used with other drugs to counteract this effect  Dangerous when used with renal failure; the failing kidney cannot excrete extra magnesium, resulting in accumulation 21 Antacids: Magnesium Salts (Cont.)  Examples  Hydroxide salt: magnesium hydroxide (Milk of Magnesia)  Carbonate salt: Gaviscon (also a combination product)  Combination products such as Maalox, Mylanta (aluminum and magnesium) 22  Antacids: Calcium Salts  Many forms but carbonate is most common  May cause constipation, kidney stones  Also not recommended for patients with renal disease—may accumulate to toxic levels  Long duration of acid action—may cause increased gastric acid secretion (hyperacidity rebound)  Often advertised as an extra source of dietary calcium  Example: Tums (calcium carbonate) 23  Antacids: Sodium Bicarbonate  Highly soluble  Buffers the acidic properties of HCl  Quick onset but short duration  May cause metabolic alkalosis  Sodium content may cause problems in patients with heart failure (HF), hypertension, or renal insufficiency. 24  Audience Response System Question #1 A patient who has chronic renal failure wants to self- treat with an antacid for occasional heartburn. Which medication is the best choice for this patient? A. A magnesium-containing antacid B. A calcium-containing antacid C. An aluminum-containing antacid D. Because of renal problems, the patient should not take antacids for this problem. NOTE: No input is required to proceed. 25  Answer to System Question #1 ANS: C Aluminum- and sodium-based antacids are recommended for patients with renal compromise because they are more easily excreted. Both calcium- and magnesium-based antacids are more likely to accumulate to toxic levels in patients with renal disease and are often avoided in this patient group. 26  Antacids and Antiflatulents  Antiflatulents: used to relieve the painful symptoms associated with gas  Several drugs are used to bind or alter intestinal gas and are often added to antacid combination products.  simethicone 27  Antacids: Adverse Effects  Minimal and depend on the compound used  Overuse: metabolic alkalosis  Aluminum and calcium: constipation  Magnesium: diarrhea  Calcium: kidney stones, rebound hyperacidity  Calcium carbonate: produces gas and belching; often combined with simethicone 28  Antacids: Drug Interactions  Adsorption of other drugs to antacids  Reduces the ability of the other drug to be absorbed into the body  Chelation  Chemical binding, or inactivation, of another drug  Produces insoluble complexes  Result: reduced drug absorption 29 Antacids: Drug Interactions (Cont.)  Increased stomach pH  Increased absorption of basic drugs  Decreased absorption of acidic drugs  Increased urinary pH  Increased excretion of acidic drugs  Decreased excretion of basic drugs 30 Histamine 2 (H2) Receptor Antagonists  Reduce acid secretion  All available OTC in lower dosage forms  Most popular drugs for treatment of acid-related disorders  Cimetidine (Tagamet)  Nizatidine (Axid)  Famotidine (Pepcid)  Ranitidine (Zantac) was taken off the market in 2020 31  H2 Antagonists: Mechanism of Action  Competitively block the H2 receptor of acid- producing parietal cells  Reduced hydrogen ion secretion from the parietal cells  Increase in the pH of the stomach  Relief of many of the symptoms associated with hyperacidity-related conditions 32  H2 Antagonists: Drug Effect and Indications  Drug effect  Suppressed acid secretion in the stomach  Indications  Gastroesophageal reflux disease (GERD)  PUD  Erosive esophagitis  Adjunct therapy to control upper GI bleeding  Zollinger-Ellison syndrome 33  H2 Antagonists: Adverse Effects  Overall, very few adverse effects  Central nervous system adverse effects in elderly patients include confusion and disorientation.  Cimetidine may induce impotence and gynecomastia.  Thrombocytopenia has been reported with famotidine. 34  H2 Antagonists: Drug Interactions  Cimetidine (Tagamet)  Binds with P-450 microsomal oxidase system in the liver, resulting in inhibited oxidation of many drugs and increased drug levels  All H2 antagonists may inhibit the absorption of drugs that require an acidic GI environment for absorption.  Because of its potential to cause drug interactions, cimetidine has been largely replaced by famotidine.  Cimetidine is still used to treat certain allergic reactions. 35  H2 Antagonists: Drug Interactions (Cont.)  Smoking has been shown to decrease the effectiveness of H2 blockers.  For optimal results, H2 receptor antagonists are taken 1 to 2 hours before antacids. 36  Audience Response System Question #2 When working with an older patient who has been admitted for a possible GI bleed, the nurse identifies which drug as having the potential to cause confusion and disorientation? A. An antacid B. A PPI C. An H2 antagonist D. A mucosal protectant NOTE: No input is required to proceed. 37  Answer to System Question #2 ANS: C H2 antagonists may cause confusion and disorientation in older adults. 38  Proton Pump Inhibitors  The parietal cells release positive hydrogen ions (protons) during HCl production.  This process is called the proton pump.  H2 blockers and antihistamines do not stop the action of this pump. 39  Proton Pump Inhibitors (Cont.)  Lansoprazole (Prevacid)  Omeprazole (Prilosec)  Rabeprazole (AcipHex)  Pantoprazole (Protonix)  Esomeprazole (Nexium)  Dexlansoprazole (Dexilant) 40  Proton Pump Inhibitors: Mechanism of Action  Irreversibly bind to H+/K+ ATPase enzyme  This bond prevents the movement of hydrogen ions from the parietal cell into the stomach.  Results in achlorhydria—all gastric acid secretion is temporarily blocked.  To return to normal acid secretion, the parietal cell must synthesize new H+/K+ ATPase. 41  Proton Pump Inhibitors: Indications  GERD  Erosive esophagitis  Short-term treatment of active duodenal and benign gastric ulcers  Zollinger-Ellison syndrome  Nonsteroidal antiinflammatory drug (NSAID)– induced ulcers  Stress ulcer prophylaxis  Treatment of H. pylori–induced ulcers  Given with an antibiotic 42  Proton Pump Inhibitors: Adverse Effects  PPIs are generally well tolerated.  Possible predisposition to GI tract infections: Clostridium difficile  Osteoporosis and risk of wrist, hip, and spine fractures in long-term users  Pneumonia  Depletion of magnesium  Link between PPIs and dementia as well as development of systemic lupus erythematous 43  Proton Pump Inhibitors: Drug Interactions  Increase serum levels of diazepam and phenytoin  Warfarin: increased chance of bleeding  Absorption of ketoconazole, ampicillin, iron salts, and digoxin  Clopidogrel  Sucralfate: may delay the absorption of PPIs  Food may decrease absorption of the PPIs. 44  Miscellaneous Acid-Controlling Drugs  Sucralfate (Carafate)  Misoprostol (Cytotec)  Simethicone (Mylicon) 45  Sucralfate (Carafate)  Cytoprotective drug (mucosal protectant)  Used for stress ulcers, peptic ulcer disease  Attracted to and binds to the base of ulcers and erosions, forming a protective barrier over these areas  Protects these areas from pepsin, which normally breaks down proteins (making ulcers worse) 46  Sucralfate (Carafate) (Cont.)  Little absorption from the gut  May cause constipation, nausea, and dry mouth  May impair absorption of other drugs; give other drugs at least 2 hours before sucralfate  Do not administer with other medications  Binds with phosphate; may be used in chronic renal failure to reduce phosphate levels 47  Audience Response System Question #3 When teaching a patient about sucralfate (Carafate) therapy, which of the following statements will the nurse include? A. “Take sucralfate 1 hour before your other medications.” B. “Sucralfate is administered once daily upon waking up.” C. “Sucralfate acts systemically to heal gastric ulcers.” D. “Sucralfate promotes ulcer healing.” NOTE: No input is required to proceed. 48  Answer to System Question #3 ANS: D Sucralfate forms a protective barrier that can be thought of as a liquid bandage, binds to the exposed proteins of ulcers and erosions, and limits the access of pepsin. Pepsin is an enzyme that normally breaks down proteins in food but can have the same effect on GI epithelial tissue, either causing ulcers or making them worse. Sucralfate also binds and concentrates epidermal growth factor, present in the gastric tissues, which promotes ulcer healing. Other drugs should be taken at least 2 hours ahead of sucralfate. Its effects are transient and multiple daily dosing (up to four times daily) is therefore needed. Sucralfate acts locally, not systemically, binding directly to the surface of an ulcer. 49  Misoprostol (Cytotec)  Prostaglandin E analogue  Prostaglandins have cytoprotective activity.  Protect gastric mucosa from injury by enhancing local production of mucus or bicarbonate  Promote local cell regeneration  Help to maintain mucosal blood flow 50  Misoprostol (Cytotec) (Cont.)  Used for prevention of NSAID-induced gastric ulcers  Doses that are therapeutic enough to treat duodenal ulcers often produce abdominal cramps and diarrhea. 51  Simethicone  Antiflatulent drug  Used to reduce the discomforts of gastric or intestinal gas (flatulence)  Alters elasticity of mucus-coated gas bubbles, breaking them into smaller ones  Result is decreased gas pain and increased expulsion via mouth or rectum. 52  Audience Response System Question #4 Simethicone (Mylicon) is often combined with calcium carbonate antacids because of what effect? A. An increased antacid effect will result when these drugs are given in combination. B. Simethicone helps to reduce the gas that is caused by the calcium antacids. C. Simethicone reduces the diarrhea that is caused by the calcium. D. Simethicone improves the taste of the calcium tablets, which must be chewed. NOTE: No input is required to proceed. 53  Answer to System Question #4 ANS: B Calcium carbonate neutralization will produce gas and possibly belching, so the addition of simethicone is intended to reduce this effect. Simethicone alters elasticity of mucus-coated gas bubbles, breaking them into smaller ones, resulting in decreased gas pain and increased expulsion via mouth or rectum. 54  Nursing Implications: Antacids  Assess for allergies and preexisting conditions that may restrict the use of antacids, such as:  Fluid imbalances  Renal disease  GI obstruction  HF  Pregnancy  Patients with HF or hypertension should not use antacids with high sodium content. 55  Nursing Implications: Antacids (Cont.)  Use with caution with other medications because of the many drug interactions.  Most medications should be administered 1 to 2 hours after an antacid.  Antacids may cause premature dissolving of enteric-coated medications, resulting in stomach upset. 56  Nursing Implications: Antacids (Cont.)  Be sure that chewable tablets are chewed thoroughly and liquid forms are shaken well before giving.  Administer with at least 8 oz of water to enhance absorption (except for “rapid-dissolve” forms). 57  Nursing Implications: Antacids (Cont.)  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. 58  Nursing Implications: Antacids (Cont.)  Monitor for adverse effects:  Nausea, vomiting, abdominal pain, diarrhea  With calcium-containing products: constipation, acid rebound  Monitor for therapeutic response:  Notify the health care provider if symptoms are not relieved. 59  Nursing Implications: H2 Antagonists  Assess for allergies and impaired renal or liver function.  Use with caution in patients who are confused, disoriented, or older.  Take 1 to 2 hours before antacids.  For intravenous doses, follow administration guidelines. 60  Nursing Implications: Proton Pump Inhibitors  Assess for allergies and history of liver disease.  Not all are available for parenteral administration.  May increase serum levels of diazepam and phenytoin; may increase chance for bleeding with warfarin 61  Nursing Implications: Proton Pump Inhibitors (Cont.)  The granules of pantoprazole capsules may be given via NG tubes, but the NG tube must be at least 16 gauge or the tube may become clogged.  Capsule contents may be opened and mixed with apple juice but do not chew or crush delayed-release granules. 62  Audience Response System Question #5 When providing education regarding the use of PPIs, which statement will the nurse include? A. “Take the medication along with the first meal of the day.” B. “Take the medication on an empty stomach, 30 to 60 minutes before eating.” C. “Take the medication when you have symptoms of heartburn.” D. “Take the medication at bedtime with a snack.” NOTE: No input is required to proceed. 63  Answer to System Question #5 ANS: B Food may decrease absorption of the PPIs, and it is recommended that they be taken on an empty stomach. They are taken on a daily basis, not as needed for heartburn. 64