week 4 GI medications

• Acid Reducers, Antidiarrheals, Laxatives is the topic for Week 4 (NUR 2403)

Housekeeping

• There will be a class observation.
• Case study and discussion questions for GERD will be covered.
• There will be a quiz at the end of class at 1345h.

Cells in the Stomach

• Cells in the stomach secrete: hydrochloric acid (HCI), bicarbonate, pepsinogen, intrinsic factor, mucus, and prostaglandins.

Anatomy Refresher

• The stomach has three regions: cardiac, pyloric, and gastric.
• The cells of the gastric gland are the largest in number and of primary importance when discussing acid control.

Cells of the Gastric Gland

• Parietal cells produce and secrete hydrochloric acid and are the primary site of most drugs that treat acid-related disorders.
• Chief cells secrete pepsinogen, a proenzyme that becomes pepsin when exposed to acid, which breaks down proteins (proteolytic).
• Mucous cells provide a protective mucus coat that protects against self-digestion of hydrochloric acid and digestive enzymes.

Hydrochloric Acid

• Parietal cells secrete hydrochloric acid when stimulated by food, caffeine, chocolate, and alcohol.
• The stomach maintains a pH of 1 to 4, which aids in the proper digestion of food and defending against microbial infection via the GI tract.
• Large fatty meals and emotional stress also stimulate hydrochloric acid secretion.

Parietal Cell Stimulation and Secretion

• Parietal cell stimulation and secretion involves multiple factors, including the vagus nerve, acetylcholine, histamine-2, and gastrin.
• These factors stimulate the H+/K+ ATPase pump, which releases H+ and leads to hydrochloric acid production.

Acid-Related Diseases

• Peptic ulcer diseases are gastric or duodenal ulcers that involve digestion of the GI mucosa by pepsin.
• H. pylori causes up to 90% of ulcers.
• Triple and Quadruple therapies are used in treatment.
• Common in ICU, stress-related mucosal damage occurs especially within the first 24 hours after admission.
• Factors for mucosal damage include decreased blood flow, mucosal ischemia, hypoperfusion, and reperfusion injury.
• GI bleeding is common in patients who use nasogastric tubes and ventilators.
• For prevention, a histamine receptor-blocking drug or a PPI can be administered.

Types of Acid-Controlling Drugs

• The three types are Antacids, H₂ antagonists, and Proton Pump Inhibitors (PPIs).

Antacids

• Antacids neutralize stomach acid, consisting of salts of aluminum, magnesium, calcium, or sodium bicarbonate.
• Some may contain simethicone an antiflatulent drug.
• Many aluminum- and calcium-based formulations may include magnesium.

Antacids: Mechanism of Action

• Antacids neutralize acidity but do not prevent the overproduction of acid.
• Antacids promote gastric mucosal defensive mechanisms and stimulate secretion of:
  • Mucus, which is a protective barrier against hydrochloric acid.
  • Bicarbonate facilitates buffering the acidic properties of hydrochloric acid.
  • Prostaglandins which prevent the activation of the proton pump.

Antacids: Drug Effects

• Antacids reduce pain and reflux related to acid disorders.
• Gastric pH rising one point, from 1.3 to 2.3, results in 90% neutralization of the acid.
• Antacids provide acute relief of symptoms stemming from peptic ulcer, gastritis, gastric hyperacidity, and heartburn disorders.

Antacids: Types

• Antacids can be used alone or in combination, such as Aluminum hydroxide, Magnesium hydroxide, Calcium, Sodium bicarbonate, or Simethicone.
• OTC formulations can be available as capsules and tables, powders, chewable tablets, suspensions, and effervescent granules and tablets.

Antacids: Aluminum Salts

• They have constipating effects, commonly used with magnesium to counteract constipation.
• Often recommended for patients with renal disease.
• Can be used in combination products (aluminum and magnesium), such as Antacid Plus®, Diovol®, Gelusil®, and Maalox®.

Antacids: Magnesium Salts

• Commonly cause diarrhea used with other drugs to counteract this.
• They are dangerous when used with renal failure because of the failing kidney cannot excrete extra magnesium, resulting in accumulation.
• Milk of magnesia is an example, such as magnesium hydroxide and mineral oil (Magnolox®).

Antacids: Calcium Salts

• Carbonate is the most common, which may cause constipation and kidney stones.
• Not recommended for patients with renal disease can cause hyperacidity rebound from their long duration.
• Marketed as an extra source of dietary calcium. -Calcium carbonate and simethicone (Maalox, Rolaids®)

Antacids: Sodium Bicarbonate

• Buffers the acidic properties of hydrochloric acid with a quick onset but short duration.
• May cause metabolic alkalosis.
• Sodium content may cause problems in patients with HF and HTN.

Antacids: Contraindications

• Severe renal failure or electrolyte disturbances can result from accumulation of electrolytes in the antacids themselves.
• Antacids stimulate gastrointestinal motility, contraindicated in gastrointestinal obstruction.
• There are interactions with many other meds, requiring a 2-hour rule to avoid effecting absorption.

H₂ Receptor Antagonists

• Reduce acid secretion and available OTC in lower-dosage forms.
• Popular drugs for treatment of acid-related disorders incldue cimetidine, ranitidine hydrochloride (Zantac®), and famotidine (Pepcid®).

H₂ Antagonists: Mechanism of Action

• Competitively block the H₂ receptor of acid-producing parietal cells.
• Reduce hydrogen ion secretion from the parietal cells; Suppressed acid secretion in the stomach, and Increased pH of the stomach.
• Relieve many symptoms associated with ailments such as Gastroesophageal reflux disease (GERD), Petpic ulcer disease, Erosive esophagitis, Adjunct Therapy to control upper gastrointestinal bleeding, and Zollinger-Elliston syndrome.

H₂ Antagonists: Adverse Effects

• Include very few adverse effects overall.
• Elderly people may experience central nervous system adverse effects such as confusion and disorientation.
• Cimetidine can cause erectile dysfunction and gynecomastia.
• Thrombocytopenia has been reported with ranitidine and famotidine

H₂ Antagonists: Drug Interactions

• Effectiveness can be decreased from smoking.
• Take H₂ receptor antagonists 1 hour before antacids for optimal outcomes.
• Inhibit absorption of drugs that require an acidic gastrointestinal environment for absorption.
• Cimetidine has been mostly replaced by ranitidine and famotidine because of interactions primarily r/t gastric pH.

Proton Pump Inhibitors

• Parietal cells releasing positive hydrogen ions (protons) during hydrochloric acid production is called the proton pump.
• H₂ blockers do not stop its activity.

Proton Pump Inhibitors: MOA

• Irreversibly bind to H+/K+ adenosine triphosphatase (ATPase) enzyme.
• Prevents the movement of hydrogen ions from the parietal cell into the stomach.
• Results in achlorhydria-all gastric acid secretion is temporarily blocked.
• The parietal cell must synthesis new H+/K+ ATPase to return to acid secretion.

Proton Pump Inhibitors

• Examples of PPIs are lansoprazole (Prevacid®), omeprazole (Losec®), rabeprazole sodium (Pariet®), pantoprazole sodium (Pantoloc®), esomeprazole trihydrate (Nexium®), and dexlansoprazole (Dexilant®).
• The indications for taking PPIs consist of these ailments: gastroesophageal reflux disease, Erosive esophagitis, Short-term treatment of active duodenal and benign gastric ulcers, Zollinger-Ellison syndrome, Nonsteroidal anti-inflammatory drug (NSAID)-induced ulcers, stress ulcer prophylaxis and treatment of H. pylori-induced infections given with an antibiotic.

Proton Pump Inhibitors: Adverse Effects

• Generally well tolerated short term.
• Possible predisposition to gastrointestinal tract infection C difficile.
• Osteoporosis and increased risk of wrist, hip, and spine fractures in long-term users.
• Can cause pneumonia and depletion of magnesium.

Proton Pump Inhibitors: Interactions

• Increase serum levels of diazepam and phenytoin, increased chance of bleeding when paired with Warfarin.
• Impairs absorption of ketoconazole, ampicillin, iron salts, and digoxin.
• Sucralfate may delay the absorption of PPIs and food may decrease their absorption.

Sucralfate

• Mucosal protectants for stress ulcers and peptic ulcer disease.
• Attracted to/binds to the base of ulcers and erosions, for a protective barrier.
• May cause constipation, nausea, and dry mouth.
• May impair absorption of other drugs; other drugs may be given at least 2 hours before sucralfate for this reason.
• Binds with phosphate; may be beneficial in chronic renal failure to reduce phosphate levels.

Simethicone

• Simethicone is an antiflatulent drug.
• Reduces the discomforts of gastric or intestinal gas and alters elasticity of mucus-coated gas bubbles to break them into smaller ones.
• Decreased gas pain and increased expulsion is the outcome of small intestine elasticity changes by mouth or rectum.

Nursing Implications: Antacids

• Chewable tablets need to be chewed thoroughly; liquid forms need to be shaken well before giving.
• Administer with at least 240 mL of water to enhance absorption.
• Long-term self-medication with antacids may mask symptoms of serious underlying diseases like malignancy or bleeding ulcers.

Nursing Implications: H₂ Antagonists

• Assess for allergies and impaired renal or liver function.
• Use with caution in patients who are confused, disoriented, or in older adult patients.
• Take 1 to 2 hours before antacids or follow the administration guidelines for intravenous doses.

Nursing Implications: PPIs

• 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 if paired with warfarin.
• Granules may be given with nasogastric tubes after dilation.
• Capsules may be opened and mixed with apple juice, but granules should not be crushed or chewed.

Diarrhea

• Second leading cause of death in children.
• 3 or more loose or watery stools per day.
• Can be the result of IBS, diabetes, IDS, Crohn's, colitis, infection that causes choice of treatment.

Goals of Diarrhea Treatment

• Stopping the stool frequency, alleviating abdominal cramps, replenishing fluids and electrolytes, and preventing weight loss and nutritional difficulties from malabsorption.
• Focus on antidiarrheals: adsorbents, antimotility drugs (anticholinergics and opiates), and probiotics(intestinal flora modifiers and bacterial replacement drugs).

Antidiarrheals: Indications

• Adsorbents: used for milder cases
• Anticholinergics and opiates: used for more severe cases
• Probiotics: used for antibiotic-induced diarrhea

Mechanism of Action

• Adsorbents coat the walls of the Gl tract, bind to the causative bacteria or toxin, which is eliminated through stool.
  • bismuth subsalicylate (Pepto-Bismol®), and antilipemic drugs colestipol
  • Also activated Charcoal, and Cholestryramine
• Antimotility drugs: anticholinergics and opiates decrease intestinal muscles stone, peristalsis of the Gl tract, and allows for slower movement of fecal movement through the Gl tract.
  • Examples: Hyoscyamine, atropine, codeine phosphate, loperamide hydrochloride, and diphenoxylate.
• Probiotics: Intestinal Flora Modifiers are also known as bacterial replacement drugs bacteria cultures of Lactobacillus organisms.
  • They Supply missing bacteria to the Gl tract suppresses the growth of diarrhea and Example: Lactobacillus acidophilus

Antidiarrheals: Adverse Effects

• Adsorbents: Increased bleeding time, Dark stools, Confusion, Tinnitus, Metallic Taste, and Blue Gums
• Anticholinergics may cause Urinary retention, Anxiety, Drowsiness, Dry Skin, Blurred Vision, Confusion, Bradychardia, and Dizziness.
• Opiates may cause Drowsiness, Hypotension, Respiratory depression, Dizziness, and Lethargy.

Antidiarrheals: Interactions

• Adsorbents decrease the absorption of many drugs, including digoxin, quinidine sulphate, and hypoglycemic drugs.
• Anticoagulents (warfarin) with Adsorbents may cause increased bleeding or bruising.
• Toxicity may effect Methotrexale when given with Adsorbents

Antidiarrheals: Nursing Implications

• Obtain a history of bowel problems, general health, and changes in diet/illness.
• Do not give bismuth subsalicylate to kids or teenagers with chicken pox or influenza to avoid Risk of Reye's syndrome
• Use Adsorbents carefully in older adult patients and those with decreased bleeding time, disorder, or confusion.

Constipation

• Abnormally infrequent and difficult passage of feces from ingestion to defecation.
• Symptom, not a disease, and usually happens within 24-35 hours.
• Measured in Bristol stool chart.

Laxatives

• Bulk forming, Emollient (stool softeners, lubrica laxatives), Hyperosmotic, Saline, and Stimulant

Mechanism of Action

• Bulk Formers that absorb water to create a high fiber formula, increase the bowlel activity, and can be found in psyllium(Metamucil)
• Emollients that soften stools by Lubricating the fecal matter/ walls by promoting more water into the stools, and used as lubricants.
• Stimulants increase the peristalsis of the intestinal nerves through senna(Senokot)
• Hyper osmotic can increase the fecal water through sorbitol or lactulose
• Saline that create a high pressure that increase the water in the intestines that create more evacuation.

Laxatives: Inidications

• Bulk forming for Irritable Bowel syndrome
• Emollient prevent bowel movements in anorectal area
• Hyperosmotic for surgical procedures
• Saline: For surgical or diagnositc procedures
• Stimulant: for surgical diagnostic procedures

Laxatives: Adverse Effects

• Bulk forming
• Electrolyte imbalance
• Emollient Electrolyte Imbalance
• All of the groups may lead to disruptions of the electrolyte balances

Laxatives: Nursing Implications

• Not for patients who are experiencing abdominal pain
• Increase fluid
• Swallow Laxative Tablets Whole
• Patients that are taking bulk forming meds to use recommended usage, and can cause problems if taken with milk.
• Contact providers in severe cases of cramps.