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Pharmacology-Digestive System Drugs PowerPoint Presentation

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Description : Check out this medical PowerPoint presentation titled "Pharmacology- Digestive System Drugs" by Linda Self APN, MSN, CCRN.

This medical PowerPoint presentation is about various drugs available that target different parts of the digestive system to treat a range of conditions such as acid reflux, constipation, diarrhea, and inflammatory bowel disease. Some of the commonly used digestive system drugs are:

Proton Pump Inhibitors (PPIs): These drugs reduce the amount of acid produced in the stomach, thereby providing relief from acid reflux, GERD, and other acid-related conditions. Examples of PPIs include omeprazole, esomeprazole, and pantoprazole.
Antacids: Antacids are used to neutralize stomach acid, providing relief from heartburn and acid indigestion. These drugs work quickly and are available over the counter. Examples of antacids include calcium carbonate, magnesium hydroxide, and aluminum hydroxide.
H2 Receptor Blockers: H2 blockers work by blocking the action of histamine, which stimulates acid production in the stomach. These drugs are used to treat acid reflux, GERD, and peptic ulcers. Examples of H2 blockers include ranitidine, cimetidine, and famotidine.
Prokinetics: Prokinetic drugs are used to stimulate the movement of food through the digestive system. These drugs are used to treat conditions like gastroparesis and GERD. Examples of prokinetic drugs include metoclopramide and domperidone.
Laxatives: Laxatives are used to treat constipation by stimulating bowel movements. There are different types of laxatives, including bulk-forming, osmotic, stimulant, and lubricant laxatives. Examples of laxatives include psyllium, lactulose, bisacodyl, and mineral oil.
Antidiarrheals: Antidiarrheal drugs are used to treat diarrhea by slowing down bowel movements and reducing the frequency and urgency of bowel movements. Examples of antidiarrheals include loperamide and bismuth subsalicylate.
Anti-inflammatory drugs: These drugs are used to treat inflammatory bowel disease, such as Crohns disease and ulcerative colitis. Examples of anti-inflammatory drugs include mesalamine, sulfasalazine, and corticosteroids.

Its important to note that all drugs have potential side effects and may interact with other medications. Therefore, it is important to consult a healthcare professional before starting any new medication.

Tags : Digestive System Drugs, digestive system, acid reflux, constipation, diarrhea, inflammatory bowel disease, Proton Pump Inhibitors, pharmaceuticals, pharmaceuticals PowerPoint presentations

Published on : Jun 23, 2023 | Views : 927 | Downloads : 1

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Slide 1-

Nursing 3703PharmacologyDigestive System Drugs By Linda Self APN, MSN, CCRN
Slide 2-

Effects of Drugs on the Digestive System Digestive system and drug therapy have a reciprocal relationship Some medications cause GI symptoms (e.g. EES); conversely, some GI disorders alter the absorption and metabolism of drugs (liver failure) Drugs affecting the GI tract include: laxatives, antidiarrheals, antiemetics, drugs used in acid-peptic disorders . Others include cholinergics (Aricept) anticholinergics (atropine), corticosteroids and anti-infectives.
Slide 3-

Review physiology of the digestive system Organs and some associated disorders Oral cavity-stomatitis Esophagus-GERD Stomach—peptic ulcers, gastritis Small intestine—malabsorption, Inflammatory bowel Large intestine—diarrhea, constipation Pancreas—pancreatitis, Diabetes, ARDS Gallbladder—cholestasis,cholelithiasis, cholecystitis Liver—hepatitis, cirrhosis
Slide 4-

Cell protective mechanisms in stomach Secretion of mucus and bicarbonate Dilution of gastric acid by food and secretions Prevention of diffusion of HCL from the stomach lumen back into the gastric mucosal lining Presence of prostaglandin E Alkalinization of gastric secretions by pancreatic juices and bile
Slide 5-

Cell Destructive Effects in Stomach Gastric acid, secreted by parietal cells Paretal cells contain receptrors for acetylcholine, gastrin and histamine, all of which stimulate gastric acid production Acetylcholine is released by vagus nerve endings in response to stimuli, such as thinking about food
Slide 6-

Cell destructive effects cont. Gastrin is a hormone released by the stomach and duodenum in response to food ingestion. Affects parietal cells which in turn causes gastric acid to be released in stomach. Histamine is released from cells in the gastric mucosa and diffuses into nearby parietal cells Pepsin is a proteolytic enzyme that helps digest protein foods and also can digest the stomach wall
Slide 7-

Cell destructive effects H. pylori is a gram negative bacterium found in the gastric mucosa of most clients with chronic gastritis In 75% of those with gastric ulcers and in 90% of clients with duodenal ulcers Spread by oral fecal route or by iatrogenic spread Thought to affect mucosal function
Slide 8-

Peptic Ulcer Disease Gastric Ulcers Associated with stress, NSAIDs or H. pylori Manifested by painless bleeding Take longer to heal than duodenal ulcers When associated w/stress, can occur at any age With H. pylori and NSAIDs generally are in 6th or 7th decade chronic
Slide 9-

PUD cont. Duodenal Ulcers Can occur at any age Occur equally in men and women Manifested by abdominal pain Associated with cigarette smoking Also associated with NSAIDs and H. pylori
Slide 10-

Peptic Ulcer and Acid Reflux Disorders Characterized by ulcer formation in the esophagus, stomach or duodenum Occurs in areas that are exposed to gastric acid and pepsin Gastric and duodenal ulcers are more common than esophageal ulcers Parietal cells contain receptors for acetylcholine—implication of which is stimulation by/of vagus
Slide 11-

Upper GI Disorders Gastritis—acute or chronic inflammatory reaction of gastric mucosa. Usually will see peptic ulcers with gastritis Non-steroidal anti-inflammatory Drug Gastropathy Occurs with damage to mucosa by ASA or other NSAIDs Chronic ingestion causes irritation of the gastric mucosa, inhibits the synthesis of prostaglandins (which protect mucosal lining) and increasess the synthesis of leukotrienes and other substances that can cause mucosal damage
Slide 12-

Selected Upper Gastrointestinal Disorders Review p. 853 in text Include Gastritis Nonsteroidal anti-Inflammatory Drug Gastropathy Stress Ulcers Zollinger-Ellison Syndrome-rare; excessive secretion of gastric acid and a high incidence of ulcers. Caused by gastrin-secreting tumors in pancreas, stomach or duodenum. Often malignant.
Slide 13-

Gastroesophageal Reflux Disease Most common disorder of the esophagus Characterized by regurgitation of gastric contents into the esophagus Occurs most often after a meal Worse when recumbent Caused by incompetent lower esophageal sphincter Foods that cause relaxation include: etoh, caffeine, fats, chocolate, cigarrette smoking, gastric distention and medications (beta adrenergic blockers, calcium channel blockers, nitrates)
Slide 14-

GERD cont. Occurs in men, women, and children Common during pregnancy More common after 40 years of age
Slide 15-

Classifications and Individual Drugs Antacids—alkaline substances that neutralize acids. Raising the pH to approximately 3.5 neutralizes more than 90% of gastric acid and inhibits conversion of pepsinogen to pepsin. Commonly used antacids are aluminum, magnesium, and calcium compounds.
Slide 16-

Antacids Antacids vary in onset of active and dosage needed for neutralization Aluminum compounds require large doses for effectiveness. They can cause constipation, hypophosphatemia and osteomalacia. Magnesium based antacids have more rapid onset than Al++ but can cause diarrhea and hypermagnesemia Calcium compounds can cause hypercalcemia and hypersecretion of gastric acid==“rebound”
Slide 17-

Antacids May be in combinations such as aluminum and magnesium hydroxide Decreases the diarrhea and constipation Most antacids are pregnancy category C Antacids may be used in children Antacides with magnesium are contraindicated because hypermagnesemia may result Additives such as simethicone may be added pills are as effective as liquids
Slide 18-

Use in Older Adults Smaller doses as they secrete less acid May have some renal compromise Older adults often take large doses of NSAIDs H2 receptor antagonists sometimes cause more side effects Sucralfate is well tolerated PPIs are drugs of choice in this population
Slide 19-

Helicobacter pylori Requires combination of two antimicrobials and a PPI or an H2RA Use amoxicillin, clarithromycin, metronidazole or tetracycline for antibiotic portion More than antimicrobial is indicated to prevent resistance Bismuth compound is added for its antibacterial effects as well as increasing the HCO3- and mucous contents of the stomach Adding an H2RA or PPI decreases S/S and hastens healing
Slide 20-

Histamine 2 Receptor Antagonists Histamine release causes contraction of smooth muscle in bronchi, GI tract, increases permeability of capillaries,stimulation of sensory nerve endings and strong stimulation of gastric acid secretion Vagal stimulation causes release of histamine from cells in stomach, acts on receptors in parietal cells>>>>increases HCL production. Called H2 receptors
Slide 21-

Histamine 2 Receptor Antagonists Traditional antihistamines or H1 receptor antagonists generally reduce the effects of histamine in the body but do not block histamine effects on gastric acid production. Replaced as first choice drugs by the PPIs Prototype is cimetidine Generally are pregnancy category B May have multiple drug interactions and SE Available OTC and by Rx
Slide 22-

H2RA Reduce dosage in pregnancy Cimetidine affects the cytochrome p450 drug metabolizing system in the liver; may cause confusion and antiadrogenic effects (gynecomastia) Ranitidine more powerful Use for up to 8 weeks May be used long term but with variable dosing Antacids may be given concurrently to relieve pain
Slide 23-

Proton Pump inhibitors Strong inhibitors of gastric acid secretion Bind irreversibly to the gastric proton pump to prevent the release of gastric acid from parietal cells Suppresses acid secretion in response to all primary stimuli including histamine, gastric, and acetylcholine Are the drugs of first choice in erosive esophagitis, erosive gastritis and Zollinger-Ellison
Slide 24-

PPIs More effective than H2RA Faster symptom relief and faster healing Used in prevention of esophagitis Tx H. pylori associated ulcers Side effects are nausea, diarrhea and HA Long term effects??? Implications??
Slide 25-

Prostaglandin Naturally occurring prostaglandin E is produced by mucosal cells of the stomach and duodenum. It inhibits gastric acid secretion and increases mucous and bicarbonate, mucosal blood flow and mucosal repair. With inhibition of Prostaglandin E, erosion and ulceration of the gastric mucosa may occur. Implications
Slide 26-

Cytotec (misoprostol) Synthetic form of prostaglandin E Indicated for clients at high risk for GI ulceration and bleeding and in those who take NSAIDs Contraindicated in women of childbearing age and during pregnancy (see text p. 862) May induce abortion Side effects include diarrhea and abdominal cramping
Slide 27-

Sucralfate Preparation of sulfated sucrose and aluminum hydroxide that binds to normal and ulcerated mucosa Mechanism of action is unclear Thought to possible bind to the ulcer and form a protective barrier between the mucosa and gastric acid, pepsin and bile salts; and stimulating prostaglandin synthesis Effective in healing duodenal ulcers and in prevention of recurrence
Slide 28-

Sucralfate Side effects include constipation and dry mouth Must be given Bid Cannot be given with an antacid, H2RA or PPI May bind other drugs and prevent their absorption Give 2 hours before or after other drugs
Slide 29-

Effects of Acid Suppressant Drugs on Nutrients Dietary folate, iron and Vitamin B12 are better absorbed from an acidic environment Less acidic environment can cause deficiencies of these nutrients Sucralfate interferes with the absorption of the fat soluble vitamins Magnesium containing antacids interfere with absorption of Vitamin A
Slide 30-

Nursing Actions Review administration on p. 865-867
Slide 31-

Antiemetics Used to prevent or treat nausea and vomiting Vomiting is the expulsion of stomach contents through the mouth Vomiting can occur w/o nausea
Slide 32-

Origin of vomiting Vomiting center is located in medulla oblongata Stimuli are relayed to the vomiting center from the periphery (gastric mucosa, peritoneum, intestines, joints(?)) and centrally (from the cerebral cortex; vestibular apparatus and from neurons in the fourth ventricle==chemoreceptor trigger zone) sites
Slide 33-

The vomiting center, chemoreceptor trigger zone and GI tract contain benzodiazepine, cholinergic, dopamine, histamine, opiate and serotonin receptors that are stimulated by emetogenic drugs and toxins For example: chemotherapy may stimulate the CTZ which then signals the vomiting center Motion sickness—changes in body motion>>stimulate receptors in inner ear>>transmitted to the CTZ and the vomiting center
Slide 34-

Triggering the vomiting center Efferent impulses cause glottic closure Contraction of abdominal muscles and diaphragm Relaxation of the GE sphincter Reverse peristalsis Projection or expulsion
Slide 35-

Causes of nausea and vomiting Pain Emotional disturbances Radiation therapy Motion sickness Drug therapy: especially with alcohol, ASA, digoxin, anticancer drugs, antimicrobials, estrogen preparations and Opioids
Slide 36-

Causes of Nausea and Vomiting GI disorders such as inflammation of the GI tract, liver, gallbladder, pancreas, impaired GI motility and muscle tone (gastroparesis) and ingestion of food that is irritating to the mucosa Cardiovascular, infectious, neurologic or metabolic disorders
Slide 37-

Antiemetic Drugs Most have anticholinergic, antidopaminergic, antihistaminic or antiserotonergic effects Generally are more effective in prophylaxis than treatment Most act on the vomiting center, the chemoreceptor trigger zone, the cerebral cortex, vestibular apparatus or any of the above
Slide 38-

Antiemetic Drugs Phenothiazines—CNS depressants used in psychoses Block dopamine from receptor sites in the brain Act on CTZ and the vomiting center Not all phenothiazines are anti-emetics Cause drowsiness Prochlorperazine (Compazine) and promethazine (Phenergan) are examples Some are pregnancy category B, others C, should check 1st
Slide 39-

Side effects continued Extrapyramidal symptoms which include: Dyskinesias (rhythmic movements), dystonias (rhythmic jerks) and akathesia (inability to sit still) related to dopamine receptor blockade
Slide 40-

Antihistamines Prevent histamine from exerting its widespread effects on the body Classic antihistamines or H1 receptor blocking agents are thought to block the action of acetylcholine in the brain (anticholinergic) Indicated in Motion sickness Examples are Dramamine, hydroxyzine (Vistaril), meclizine (Antivert)
Slide 41-

Corticosteroids May affect prostaglandin activity in the cerebral cortex Dexamethasone and methyprednisolone are commonly used in the management of chemotherapy induced emesis, usually in combination with other anti-emetics
Slide 42-

Benzodiazepine antianxiety drugs Not classic anti-emetics but often used in multidrug regimens to prevent nausea and vomiting associated with cancer chemotherapy Inhibit cerebral cortex input to the vomiting center May give to those with anticipatory nausea before chemotherapy Example is Ativan (lorazepam)
Slide 43-

5 Hydroxytryptamine (5-HT3 or Serotonin)Receptor Antagonists Ondansetron, granisetron and dolasetron are used to prevent or treat moderate to severe nausea and vomiting r/t cancer chemotherapy, radiation therapy and postoperatively Some anticancer drugs seem to affect a subset of 5-HT3 recptors in the CTZ and the GI tract These drugs antagonize receptors both peripherally (GI) and in the CTZ to prevent activation
Slide 44-

5-HT3 receptor antagonists cont. Can be given IV or orally Side effects are mild to moderate and include: diarrhea, headache, dizziness, constipation, muscle aches and transient liver enzymes elevation Ondansetron (Zofran) is the prototype Metabolized by the liver
Slide 45-

Miscellaneous Antiemetics Dronabinol (Marinol) is a cannabinoid used in the management of nausea and vomiting associated with anticancer drugs and unrelieved by other drugs. Schedule III under federal narcotic laws Withdrawal S/S may occur Sleep disturbances
Slide 46-

Reglan Prokinetic that increases GI motility and the rate of gastric emptying by increasing the release of acetylcholine from nerve edings in the GI tract Can cause decreased n/v associated with gastroparesis Has central antiemetic effects, antagonizes the action of dopamine Can be given IV, PO or IM
Slide 47-

Reglan continued Side effects include sedation, restlessness, and extrapyramidal reactions May increase the effects of alcohol and cyclosporine and decrease the effects of cimetidine and digoxin (decrease time for passage)
Slide 48-

Emetrol Phosphorated carbohydrate solution Hyperosmolar solution with phosphoric acid OTC Felt to work by reducing smooth muscle contraction in the GI tract
Slide 49-

Scopolamine Anticholinergic drug Transdermal patch Excellent for motion sickness
Slide 50-

Contraindications When can delay or prevent diagnosis When s/s of toxicity may be masked Reglan is relatively contraindicated in Parkinson’s disease because it further dples dopamine
Slide 51-

Management Considerations 5-HT3 antagonists 1st choice in chemotherapy induced or postoperative N/V Drugs with anticholinergic and antihistaminic properties are preferred for motion sickness If ambulatory, opt for drug that causes less sedation Phenergan is used for its antihistaminic, antiemetic and sedative effects
Slide 52-

Management Considerations cont. Phenothiazines can have serious side effects Reglan may be preferred for non-obstructive gastric retention
Slide 53-

Herbals Efficacy still debatable
Slide 54-

Chemotherapy-induced Nausea and Vomiting Chemo may be given during sleeping hours Decrease food intake few hours before Tx Antiemetics should be given before the emetogenic Tx and may be given for 2-3 days 5-HT2 receptor antagonists are drugs of choice for this indication Reglan is valid option but may need to give diphenhydramine to prevent the EPS Sometimes combo of steroid and 5-HT3 RA useful
Slide 55-

Laxatives and Cathartics When stomach and duodenum are distended with food, gastrocolic and duodenocolic reflexes are initiated The cerebral cortex controls the defecation reflex so that defecation can occur at acceptable times and places In people who inhibit the defecation reflex or fail to respond to the urge to defecate, constipation develops
Slide 56-

Laxatives are chemical substances that act to facilitate passage of bowel contents Cathartics—a purgative action of the bowels, action is stronger and generally produces elimination of liquid stools
Slide 57-

Indications for Use Reduce cholesterol Obtain stool sample Accelerate excretion of parasites after anthelminthics started Accelerate elimination of potentially toxic substances (Kayexalate) Pre-op Prevent straining at stool w/CAD, hemorrhoids Relieve constipation in pregnancy, in the elderly; in children with megacolon, and in those w/decreased motility
Slide 58-

Laxatives and cathatics should not be used in the presence of undiagnosed abdominal pain Could cause an inflamed organ to rupture Oral agents are contraindicated in intestinal obstruction and fecal impaction
Slide 59-

Laxatives Bulk-forming laxatives—Citrucel, Metamucil Surfactant Laxatives—mainly prevent straining. They allow water to penetrate stool and act as detergent to facilitate admixing of fat and water in the stool. Colace (docusate) or Surfak. Saline—magnesium citrate. Nulytely.Increase osmotic pressure in intestinal lumen.Not safe for frequent use. Affect fluids and lytes.
Slide 60-

Cathartics Stimulant type are the strongest and most abused Cascara,bisacodyl, castor oil and senna products Mineral oil is a lubricant laxative. It slows colonic absorption of water.
Slide 61-

Other Lactulose—a disaccharide that is not absorbed from the GI tract. Pulls water into intestinal lumen. Used to treat constipation and hepatic encephalopathy. Lactulose reduces production of ammonia in the intestine. Can affect lyte and water balance. Sorbitol—monosaccharide that puls water into the intestinal lumen and has laxative effects. It is given with Kayexalate (potassium removing resin to treat hyperkalemia).
Slide 62-

Laxative Abuse Public health problem in elderly Use in patients with cancer What is normal? What are some measures to prevent constipation?
Slide 63-

Safety in Use Saline cathartics must be used cautiously in the renally impaired Lactulose may be indicated in those with hepatic encephalopathy Seen frequently in form of enemas in hyperkalemia in hospital
Slide 64-

Antidiarrheals Diarrhea is a symptom of numerous conditions that increase bowel motility; cause secretion or retention of fluids in the intestinal lumen and cause inflammation or irritation of the GI tract. End result: bowel contents are rapidly propelled and absorption of fluids and electrolytes is limite.d
Slide 65-

Causes of Diarrhea Abuse of laxatives Intestinal infections—E. Coli 0157:H7 (can result in a hemolytic uremic syndrome), Traveller’s diarrhea (E. coli), Campylobacter jejuni, Salmonella, Shigella, rotatvirus Inflammatory bowel diseases Drug therapy—pseudomembranous colitis—Clostridium difficile (anaerobic, spore forming rods)
Slide 66-

Antidiarrheals Opiate related drugs Paregoric Defenoxin with atropine—Motofen Diphenoxylate with atropine--Lomotil
Slide 67-

Antibacterials Azithromycin for Traveller’s diarrhea Cipro—E.coli, Camylobacter, Shigella EES—amebiasis Flagyl—Clostridium difficile Bactrim-Traveller’s diarrhea Vancomycin—Clostridium difficile, even in form of enemas
Slide 68-

Miscellaneous Questran—Crohns’. Binds and inactivates bile salts in the intestine. Octreotide—diarrhea associated with HIV, carcinoid tumors, cancer therapies or intractable diarrhea caused by other drugs. Pancreatin—pancreatic enzymes used for replacement in patients w/deficiency of pancreatic enzymes