Chapter 57: Drugs Affecting Gastrointestinal Secretions Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Underlying Causes of GI Disorders Dietary Excess Stress Hiatal Hernia Esophageal Reflux Adverse Drug Effects Peptic Ulcer Disease Copyright © 2020 Wolters Kluwer • All Rights Reserved Effect of Drugs on GI Secretions Decrease GI secretory activity Block the action of GI secretions Form protective coverings on the GI lining to prevent erosion from GI secretions Replace missing GI enzymes that the GI tract or ancillary glands and organs can no longer produce Copyright © 2020 Wolters Kluwer • All Rights Reserved Peptic Ulcer Disease Definition o Erosions in the lining of the stomach and adjacent areas of the GI tract Symptoms o Gnawing, burning pain, often occurring after meals Cause o Bacterial infection by Helicobacter pylori bacteria Copyright © 2020 Wolters Kluwer • All Rights Reserved Drugs Used to Treat GERD and Ulcers Histamine-2 (H2) Antagonists: Block the release of hydrochloric acid in response to gastrin Antacids: Interact with acids at the chemical level to neutralize them Proton Pump Inhibitors: Suppress the secretion of hydrochloric acid into the lumen of the stomach GI Protectants: coat any injured area in the stomach to prevent further injury from acid Prostaglandins: inhibit the secretion of gastrin and increase the secretion of the mucous lining of the stomach, providing a buffer Copyright © 2020 Wolters Kluwer • All Rights Reserved Sites of Actions of Drugs Affecting Gastrointestinal Secretions Copyright © 2020 Wolters Kluwer • All Rights Reserved Use of Agents Affecting Gastrointestinal Secretions Across the Lifespan Copyright © 2020 Wolters Kluwer • All Rights Reserved Histamine-2 (H2) Antagonists #1 Block the release of hydrochloric acid in response to gastrin o Cimetidine (Tagamet HB) o Ranitidine (Zantac) o Famotidine (Pepcid) o Nizatidine (Axid) Copyright © 2020 Wolters Kluwer • All Rights Reserved Histamine-2 (H2) Antagonists #2 Actions o Selectively block histamine-2 receptor sites o This blocking leads to a reduction in gastric acid secretion and reduction in overall pepsin production Indications o Short-term treatment of active duodenal ulcer or benign gastric ulcer o Treatment of pathological hypersecretory conditions such as Zollinger–Ellison syndrome o Prophylaxis of stress-induced ulcers and acute upper GI bleeding in critical patients Copyright © 2020 Wolters Kluwer • All Rights Reserved Histamine-2 (H2) Antagonists #3 Indications (cont.) o Treatment of erosive gastroesophageal reflux o Relief of symptoms of heartburn, acid indigestion, and sour stomach (OTC preparations) Pharmacokinetics o Readily absorbed after oral administration o Metabolized in the liver and excreted in urine Contraindications o Known allergy Copyright © 2020 Wolters Kluwer • All Rights Reserved Histamine-2 (H2) Antagonists #4 Caution o Pregnancy or lactation o Hepatic or renal dysfunction Adverse Effects o GI effects o CNS effects o Cardiac arrhythmias and hypotension Drug-Drug Interactions o Warfarin, phenytoin, beta blockers, alcohol, quinidine, lidocaine, theophylline, chloroquine, benzodiazepines, nifedipine, pentoxifylline, tricyclics, procainamide, and carbamazepine Copyright © 2020 Wolters Kluwer • All Rights Reserved Nursing Considerations for Histamine-2 (H2) Antagonists Assess: o History and Physical Exam and known allergy o Impaired renal or hepatic function o Skin, pregnancy and lactation o Neurological status, including orientation and affect o cardiopulmonary status, including pulse, blood pressure, abdomen and liver, and appropriate lab values Copyright © 2020 Wolters Kluwer • All Rights Reserved Prototype Histamine-2 (H2) Antagonists Copyright © 2020 Wolters Kluwer • All Rights Reserved Question #1 Drugs act in several ways on the secretions of the GI tract. Which action affects the GI secretions least? A. Decreases secretory activity B. Blocks secretions C. Replaces secretions D. Prevents erosions Copyright © 2020 Wolters Kluwer • All Rights Reserved Answer to Question #1 C. Replaces secretions Rationale: The effects of drugs on GI secretions: decrease GI secretory activity; block the action of GI secretions; form protective coverings on the GI lining to prevent erosion from GI secretions; replace missing GI enzymes that the GI tract or ancillary glands and organs can no longer produce Copyright © 2020 Wolters Kluwer • All Rights Reserved Antacids #1 A group of inorganic chemicals that neutralize stomach acid o Sodium bicarbonate (Bell-ans) o Calcium carbonate (Oystercal, Tums, and others) o Magnesium salts (Milk of Magnesia, and others) o Aluminum salts (Amphojel, and others) Copyright © 2020 Wolters Kluwer • All Rights Reserved Antacids #2 Actions o Neutralize stomach acid by direct chemical reaction Indications o Symptomatic relief of upset stomach associated with hyperacidity, as well as hyperactivity Contraindications o Allergy Caution o Any condition that can be exacerbated by electrolyte imbalance o GI obstruction Copyright © 2020 Wolters Kluwer • All Rights Reserved Antacids #3 Adverse Effects o Relate to their effects on acid-base levels and electrolytes o Rebound acidity o Alkalosis o Hypercalcemia o Constipation or diarrhea o Hypophosphatemia Drug-Drug Interactions o Affect the absorption of many other drugs Copyright © 2020 Wolters Kluwer • All Rights Reserved Nursing Considerations for Antacids Assess: o History and Physical Exam and known allergy o Renal dysfunction, electrolyte disturbances, and current status of pregnancy or lactation o Abdomen and BS, mucus membranes and appropriate lab values Copyright © 2020 Wolters Kluwer • All Rights Reserved Prototype Antacids Copyright © 2020 Wolters Kluwer • All Rights Reserved Proton Pump Inhibitors #1 Suppress the secretion of hydrochloric acid into the lumen of the stomach o Omeprazole (Prilosec) o Esomeprazole (Nexium) o Lansoprazole (Prevacid) o Dexlansoprazole (Kapidex) o Pantoprazole (Protonix) o Rabeprazole (Aciphex) Copyright © 2020 Wolters Kluwer • All Rights Reserved Proton Pump Inhibitors #2 Actions o Act at specific secretory surface receptors to prevent the final step of acid production and thereby decrease the level of acid in the stomach Indications o Short-term treatment of active duodenal ulcers, GERD, erosive esophagitis, and benign active gastric disease o Long-term treatment of pathological hypersecretory conditions Pharmacokinetics o Acid labile, rapidly absorbed in the GI tract o Metabolized in the liver and excreted in the urine Copyright © 2020 Wolters Kluwer • All Rights Reserved Proton Pump Inhibitors #3 Contraindications o Allergy Caution o Pregnancy or lactation Adverse Effects o CNS effects: Dizziness, headache, asthenia, vertigo, insomnia, apathy o GI Effects: Diarrhea, abdominal pain, and tongue atrophy o Upper respiratory tract symptoms: Cough, stuff nose, hoarseness, and epistaxis o Other: Rash, alopecia, pruritis, dry skin, back pain, and fever Copyright © 2020 Wolters Kluwer • All Rights Reserved Proton Pump Inhibitors #4 Drug-Drug Interactions o Benzodiazepines, phenytoin, warfarin o Ketoconazole, theophylline o Sucralfate o Clopidogrel Copyright © 2020 Wolters Kluwer • All Rights Reserved Nursing Considerations for Proton Pump Inhibitors Assess: o History and Physical Exam and known allergy o Pregnancy and lactation, skin, neurological status, including level of orientation, affect, and reflexes o Abdomen and BS and respiratory status, including respiratory rate and rhythm Copyright © 2020 Wolters Kluwer • All Rights Reserved Prototype Proton Pump Inhibitors Copyright © 2020 Wolters Kluwer • All Rights Reserved GI Protectant #1 Coat any injured area in the stomach to prevent further injury from acid o Sucralfate (Carafate) Copyright © 2020 Wolters Kluwer • All Rights Reserved GI Protectant #2 Actions o Forms an ulcer-adherent complex at duodenal ulcer sites, protecting the sites against acid, pepsin, and bile salts Indications o Promote ulcer healing Pharmacokinetics o Rapidly absorbed, metabolized in the liver, and excreted in feces Contraindications o Allergy o Renal failure Copyright © 2020 Wolters Kluwer • All Rights Reserved GI Protectant #3 Caution o Pregnancy or lactation Adverse Effects o GI effects – Constipation, diarrhea, nausea, indigestion, gastric discomfort, dry mouth o Dizziness o Sleepiness o Vertigo o Skin rash o Back pain Copyright © 2020 Wolters Kluwer • All Rights Reserved GI Protectant #4 Drug-Drug Interactions o Aluminum salts o Phenytoin, fluoroquinolone, or penicillamine Copyright © 2020 Wolters Kluwer • All Rights Reserved Nursing Considerations for Antipeptic Agent Assess: o History and Physical Exam and known allergy o Pregnancy and lactation, skin, neurological status, including level of orientation, affect, and reflexes o Abdomen and BS and respiratory status, including respiratory rate and rhythm Copyright © 2020 Wolters Kluwer • All Rights Reserved Prototype GI Protectant Copyright © 2020 Wolters Kluwer • All Rights Reserved Prostaglandin #1 Protect the stomach lining o Synthetic prostaglandin E analogue misoprostol (Cytotec) 1 Copyright © 2020 Wolters Kluwer • All Rights Reserved Prostaglandin #2 Actions o Inhibits gastric acid secretion and increases bicarbonate and mucous production in the stomach Indications o Prevention of NSAID-induced gastric ulcers o Treatment of duodenal ulcers Pharmacokinetics o Rapidly absorbed from GI tract, metabolized in the liver, and excreted in the urine Contraindications o Pregnancy Copyright © 2020 Wolters Kluwer • All Rights Reserved Prostaglandin #3 Caution o Lactation Adverse Effects o GI effects – Nausea, diarrhea, abdominal pain, flatulence, vomiting, dyspepsia, and constipation o GU effects – Miscarriages, excessive bleeding, spotting, cramping, hypermenorrhea, dysmenorrhea, and other menstrual disorders Copyright © 2020 Wolters Kluwer • All Rights Reserved Nursing Considerations for Prostaglandin Assess: o History and Physical Exam and known allergy o Pregnancy and lactation, skin, neurological status, including level of orientation, affect, and reflexes o Abdomen and BS and respiratory status, including respiratory rate and rhythm Copyright © 2020 Wolters Kluwer • All Rights Reserved Prototype Prostaglandins Copyright © 2020 Wolters Kluwer • All Rights Reserved Digestive Enzymes #1 Substances produced in the GI tract to break down foods into usable nutrients o Saliva substitute (Mouth Kote, Salivart) o Pancrelipase (Creon, Pancrease) Copyright © 2020 Wolters Kluwer • All Rights Reserved Digestive Enzymes #2 Actions o Saliva substitute – Contains electrolytes and carboxymethylcellulose to act as a thickening agent in dry mouth conditions o Pancreatic enzymes are replacement enzymes that help the digestion and absorption of fats, proteins, and carbohydrates Indications o Replacement therapy Copyright © 2020 Wolters Kluwer • All Rights Reserved Digestive Enzymes #3 Contraindications o Saliva – Allergy o Pancreatic enzymes - Allergy Caution o Saliva – CHF, hypertension, or renal failure o Pancreatic enzyme – Pregnancy and lactation Copyright © 2020 Wolters Kluwer • All Rights Reserved Digestive Enzymes #4 Adverse Effects o Saliva – Complications from abnormal electrolytes – increased levels of magnesium, sodium, or potassium o Pancreatic enzyme – GI irritation, nausea, abdominal cramps, and diarrhea Copyright © 2020 Wolters Kluwer • All Rights Reserved Nursing Considerations for Digestive Enzymes Assess: o History and Physical Exam and known allergy o Heart failure or hypertension, pregnancy and lactation o Abdomen and BS, mucus membranes and appropriate lab values Copyright © 2020 Wolters Kluwer • All Rights Reserved Prototype Digestive Enzymes Copyright © 2020 Wolters Kluwer • All Rights Reserved Question #2 Please answer the following statement as true or false. There is a drug-drug interaction between the antipeptides and penicillin. Copyright © 2020 Wolters Kluwer • All Rights Reserved Answer to Question #2 False Rationale: Drug-to-drug interactions include aluminum salts, phenytoin, fluoroquinolone, or penicillamine. Copyright © 2020 Wolters Kluwer • All Rights Reserved Question #3 What H2 antagonist has been associated with antiandrongenic effects? A. Famotidine B. Cimetidine C. Nizatidine D. Ranitidine Copyright © 2020 Wolters Kluwer • All Rights Reserved Answer to Question #3 B. Cimetidine Rationale: Cimetidine was the first drug in this class to be developed. It has been associated with antiandrongenic effects, including gynecomastia and galactorrhea. Copyright © 2020 Wolters Kluwer • All Rights Reserved
