Drugs Affecting the Gastrointestinal System and Nutrition

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Drugs Affecting the Gastrointestinal System and
Nutrition

• Jan Bazner-Chandler MSN, CNS, RN, CPNP

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Acid-related Pathophysiology

• Hydrochloric acid (HCL) aids in digestion and
  serves as a barrier to infection.
• Pepsinogen is an enzyme that digests dietary
  protein.
• Mucous protects the lining of the stomach from
  both HCL and digestive enzymes.
• Prostaglandins has an anti-inflammatory and
  protective function.

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Antacids

• Are basic compounds used to neutralize stomach
  acid.

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OTC Products

• Antacids were the most common products used for
  acid-indigestion until the 1970s when
  histamine-2 (H2 antagonists) were developed.

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Action

• Primary drug effect of antacids is the reduction
  of symptoms associated with acid-related
  disorders pain and reflux (heartburn)
• Raises gastric pH from 1.3 to 1.6.

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Indications

• Acute relief of symptoms associated with
• peptic ulcer disease (PUD)
• Gastritis
• gastric hyperacidity
• Heartburn or gastro esophageal reflux (GEF)

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GERD

• Most common disorder of esophagus
• Characterized by regurgitation of gastric
  contents into esophagus and exposure of
  esophageal mucous to gastric acid and pepsin.
• Main symptom is heart burn - occurs after eating
• Cause is thought to be incompetent lower
  esophageal sphincter

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GERD
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Peptic Ulcer Disease

• Ulcer formation in the esophagus, stomach or
  duodenum
• Mucous exposed to gastric acid and pepsin
• Imbalance between cell-destructive and
  cell-protective effects
• Gastric acid and pepsin
• H. pylori infectious process

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Peptic Ulcer Disease
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Adverse Effects

• Magnesium preparations especially milk of
  magnesium or MOM can cause diarrhea.
• Calcium products can cause kidney stones.
• Sodium bicarbonate products can cause systemic
  alkalosis.
• Self-treatment can result in masking symptoms of
  a disease (bleeding ulcer or stomach cancer).

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Keep away from small children

• Alkalosis

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Contraindications

• Allergy to the drug
• Severe renal failure
• Electrolyte disturbances
• Gastro intestinal obstruction

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Interaction

• May effect absorption of other drugs.
• Chemically inactivates certain drugs
• Increased stomach pH decreasing absorption of
  acidic drugs

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OTC Preparations

• Magnesium-containing antacids
• Gaviscon Liquid, Milk of Magnesium
• Aluminum-containing antacids
• Amphogel, Maalox
• Sodium-containing antacids
• Alka-seltzer, Tums

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Gelusil / Mylanta
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Administration

• Chewable forms needs to be thoroughly chewed.
• Liquid forms need to be shaken well before
  taking.
• Take with 8 ounces of water to enhance
  absorption.
• Do not take within 1 to 2 hours of taking other
  medications may effect absorption

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H 2 Antagonists

• H2 receptor blockers
• cimetadine (Tagamet),
• ranitidine (Zantac)
• famotidine (Pepcid)
• nizatidine (Axid)

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H2 antagonist HAs

• Action
• blocks the H2 receptor of acid-producing parietal
  cells
• Reduce hydrogen ion secretions to increase pH of
  stomach

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Therapeutic Uses

• GERD or gastro-esophageal reflux
• PUD or peptic ulcer disease
• Zollinger-Ellison Syndrome (excessive gastric
  acidity)

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Adverse Effects

• Overall very low incidence of adverse effects
• May cause some CNS effects in the geriatric
  patient.
• Smoking reduces effectiveness
• H2 antagonist should be taken 1 hours before
  taking any antacids

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Proton Pump Inhibitors

• Newest drugs used in the treatment of
  acid-related disorders.
• lansopraxole (Prevacid)
• omeprazole (Prilosec)
• rabeprzole (Acephex)
• pantoprazole (Protonix)
• exomepraxole (Nexium)

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PPIs

• Action Binds directly to the hydrogen-potassium
  - ATPase pump mechanism, inhibiting the action of
  the enzyme which results in a total blockage of
  hydrogen ion secretion from the parietal cells.

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Adverse Effects

• Long term use might promote malignant gastric
  tumors.
• Concern about over prescribing resulting in
  reduction of normal acid-mediated antimicrobial
  protection.
• May need a probiotic when using PPI drug therapy.

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Miscellaneous Acid-Controlling Drugs

• sucralfate (Carafate)
• Uses long-term therapy for PUD
• Action acts locally binding directly to the
  surface of the ulcer.
• Note not used as often due to short-term action
  and multiple daily dosing.

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Cytotec

• Generic misoprostol
• Action acts on prostaglandin E analogue
• Indication reduces the incidence of gastric
  ulcers in patients taking NSAIDs.

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Mylicon

• Generic simethicone
• Action alters the elasticity of mucus-coated gas
  bubbles, causing them to break down into smaller
  ones

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Mylicon

• Used to reduce the discomfort of gastric or
  intestinal gas (flatulence)
• Used post-operatively and in post-partum patients
  to relieve gas pain.
• Often used in combination with activated charcoal
  in oral poisoning (overdose).

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Probiotics

• Probiotics are live microorganisms (in most
  cases, bacteria) that are similar to beneficial
  microorganisms found in the human gut. They are
  also called "friendly bacteria" or "good
  bacteria." Probiotics are available to consumers
  mainly in the form of dietary supplements and
  foods. They can be used as complementary and
  alternative medicine.

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Probiotics

• Probiotics are available in foods and dietary
  supplements. Examples of foods containing
  probiotics are yogurt, fermented and unfermented
  milk, miso, and some juices and soy beverages. In
  probiotic foods and supplements, the bacteria may
  have been present originally or added during
  preparation.

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Probiotics

• Most probiotics are bacteria similar to those
  naturally found in people's guts, especially in
  those of breastfed infants (who have natural
  protection against many diseases). Most often,
  the bacteria come from two groups, Lactobacillus
  or Bifidobacterium. A few common probiotics, such
  as Saccharomyces boulardii, are yeasts, which are
  different from bacteria.

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Uses

• Chronic Diarrhea
• Irritable Bowel Syndrome
• Digestive disorders
• Clients on oral or IV antibiotic therapy
• Status post abdominal surgery

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Antidiarrheals and Laxatives

• Chapter 42

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Antidiarrheal Drugs

• Used to treat diarrhea.
• Adsorbents
• Antimotility (anticholenergic and opiates)
• Intestinal flora modifiers or bacterial
  replacement drugs

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Adsorbents

• Act by coating the walls of the GI tract.
• Bind with the causative bacteria or toxin to
  their adsorbent surface for elimination through
  the stool.

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Pepto-Bismul and Kaoectate

• Generic bismuth subsalicylate
• Same chemical structure as salicylate
• use with caution in children. May cause Reyes
  Syndrome
• Use with caution in clients who are on
  anti-coagulation therapy.

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Pepto-bismol
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FDA Warning

• The main ingredient, bismuth subsalicylate, has
  been linked with Reye Syndrome, a potentially
  life-threatening disorder that has been
  associated with kids that have viral illnesses,
  especially the flu and chicken pox, and who take
  aspirin and other salicylate containing
  medications, like Pepto-Bismol.
• Label advises not to give to children under age
  12 years.

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Anticholinergics

• Used either alone or in combination with other
  antidiarrheal drugs.
• Acts by slowing GI tract motility
• Atropine
• hyoscyamine
• hyoscine

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Opiates

• Products containing Codeine
• Nursing consideration clients on opioids for
  post-operative pain control may suffer from
  constipation.
• Atropine often used to control secretions during
  surgical procedure may contribute to
  post-operative constipation

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Imodium A D

• Generic name loperamide
• Classification Opiate antidiarrheal
• Action inhibits both peristalsis in the
  intestine and intestinal secretions, decreasing
  the number of stools and their water content.
• Contraindications ulcerative colitis, acute
  diarrhea due to E-coli (Escherichia coli)

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Laxatives

• Laxative act by
• Affecting the consistency of the stool
• Increasing fecal movement through the colon
• Facilitating movement through the colon

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Constipation

• Definition abnormally infrequent and difficult
  passage of feces.
• Constipation is a symptom not a disease.

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Bulk-forming Laxatives

• Composed of water-retaining natural and synthetic
  cellulose derivates.
• Psylium is an example of natural bulk-forming
  laxative.
• Methylcellulose is an example of a synthetic
  cellulose derivative.

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Bulk-forming Laxative

• Action increases water absorption, which results
  in greater bulk of the intestinal contents.
• Tend to produce normal, formed stools.
• Action limited to GI tract so adverse effects are
  minimal.

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Citrucel (methylcellulose)
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Nursing Alert

• Have client take with 8 ounces of water.
• If powdered form needs to be mixed with 8 ounces
  of water.
• Fluid must be taken immediately to avoid swelling
  of the product in the throat or esophagus or
  fecal impaction.
• Best for clients with chronic constipation.

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Emollient laxative

• Generic classification docusate salts
• Trade names Colace, Surfak
• Action work by lowering the surface tension of
  GI fluids more water and fat are absorbed into
  the stool and intestine.

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Emollients

• Uses
• post partum
• postoperative patients
• Clients on long-term pain control
• Outcomes soft stool with easier defecation

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Mineral Oil

• Action eases the passage of stool by lubricating
  the intestines and preventing water from escaping
  the stool.
• Contraindications
• Abdominal pain
• Nausea and vomiting
• Intestinal obstruction

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Hyperosmotic Laxatives

• Glycerine
• Action promotes bowel movement by increasing the
  osmotic pressure in the intestine.
• Note given in the form of a suppository

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Stimulant Laxatives

• Through the use of natural plant products and
  synthetic chemical drugs induces intestinal
  peristalsis.
• Note the stimulant class is the most likely to
  cause dependence.

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Stimulant Laxatives

• Generic senna
• Trade Senokot
• Action stimulates the GI tract
• Adverse effects may cause abdominal pain.
• Onset of action complete bowel evacuation in 6
  to 12 hours.

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Irritable Bowel Syndrome IBS

• A condition of chronic intestinal discomfort,
  including cramps, diarrhea / or constipation.
• Two drugs to manage symptoms
• Lotronex (alostron) approved for women only
• Zelnorm (tegaserod) approved for men and women
• Action works on serotonin receptors in the
  intestinal tissue.

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Antiemetic and Antinausea Drugs

• Chapter 52

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Chemoreceptor Trigger Zone (CTZ)

• The area of the brain that is involved in the
  sensation of nausea and the action of vomiting.

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Vomiting Center (VT)

• The area of the brain that is involved in
  stimulating the physiologic events that lead to
  nausea and vomiting.

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Antiemetic Drugs

• Drugs used to relieve nausea and vomiting.
• All emetic drugs work at some site in the
  vomiting pathways.

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Syrup of Ipecac

• AAP recommendations in 2003 issued an alert to
  stop the use of this drug to induce vomiting
  after drug overdose.

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Anticholinergic Drugs

• Act by binding to and blocking acetylcholine
  receptors (ACh) in the vestibular nuclei, located
  deep in the brain.
• One drug scopolamine
• Most commonly used drug for treatment and
  prevention of nausea and vomiting associated with
  motion sickness and postoperatively.

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Antihistamines

• Action binds to H1 receptors, potentiate
  anticholinergic activity.
• Most popular OTC medications
• Generic name dimenhydrinate
• Trade name Dramamine and Benadryl
• OTC drugs used for motion sickness

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Neuroleptics

• Action antidopaminergic, antihistamine and
  anticholinergic properties.
• Trade names Compazine, Thorazine, Phenergan
• Often given as preoperative medication.
• Used to treat psychotic disorders due to effect
  on dopamine.

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Compazine Nursing Alert

• Adverse reaction extrapyramidal reaction--a
  muscle spasm of the tongue. Other typical adverse
  extrapyramidal reactions include tremors,
  drooling, and muscle spasms that usually involve
  muscles in the shoulders, neck, or eyes.
• Antidote Benadryl

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Prokinetics

• Metoclopramide
• Trade name Reglan
• Action promote the movement of substances
  through the GI tract and increases motility.
• Often given in patients getting tube feeding to
  promote gastric emptying time.

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Serotonin Blockers

• Called 5-HT3 receptor blockers because they block
  the 5-HT3 receptors in the GI tract, CTZ and
  vomiting centers VC.
• Four drugs in this category

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ondansetron

• Trade name Zofran is the prototype drug.
• Approved in 1992.
• Major break through in treating chemotherapy
  induced nausea and vomiting and postoperative
  nausea and vomiting.
• Approved for use in pregnancy.

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Side effects from all antiemetics

• May cause dizziness
• Caution with use while driving.
• CNS depression
• Hypotension

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Herbal Therapies

• Ginger Root
• May increase absorption of all oral mediations,
  may increase bleeding in clients taking Coumadin
  and Plavix.