Pharmacotherapy of GIT Disorders - Antiemetics
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Questions and Answers

What is the term used for the immediate need to vomit that is associated with gastric stasis?

  • Peristalsis
  • Nausea (correct)
  • Vomiting
  • Retching

    • Which of the following conditions can lead to vomiting due to hormonal changes?

  • Peptic ulcers
  • Food poisoning
  • Gastroenteritis
  • Pregnancy (correct)

    • What is the forcible expulsion of gastric contents through the mouth known as?

  • Vomiting (correct)
  • Nausea
  • Peristalsis
  • Retching

    • Which of the following could mask the underlying cause of vomiting?

    <p>Antiemetic drugs</p> Signup and view all the answers

    What muscle contractions are responsible for moving food through the digestive tract?

    <p>Peristalsis</p> Signup and view all the answers

    What is a common symptom accompanying vomiting, characterized by increased saliva production?

    <p>Salivation</p> Signup and view all the answers

    Which gastrointestinal disorder involves an inflammation of the stomach lining?

    <p>Gastritis</p> Signup and view all the answers

    Which of the following is NOT considered a common etiology for vomiting?

    <p>High blood pressure</p> Signup and view all the answers

    Which type of receptors do vagal afferent neurons from the gastrointestinal system express?

    <p>Serotonin and Neurokinin</p> Signup and view all the answers

    What stimulates the central vestibular nuclei from the inner ear?

    <p>Motion</p> Signup and view all the answers

    Which of the following drugs is NOT commonly associated with inducing nausea and vomiting?

    <p>Antidepressants</p> Signup and view all the answers

    What is the role of the vomiting center in the body?

    <p>Coordination of the vomiting cascade</p> Signup and view all the answers

    Which symptom is NOT considered part of the body's defense against ingested toxins?

    <p>Diarrhea</p> Signup and view all the answers

    Which factor is associated with the stimulation of the vomiting center?

    <p>Stomach irritation due to toxins</p> Signup and view all the answers

    What is a common side effect of select antidepressants?

    <p>Nausea</p> Signup and view all the answers

    Which step is NOT part of the vomiting cascade?

    <p>Opening of the epiglottis</p> Signup and view all the answers

    What is the primary use of Hyoscine (scopolamine)?

    <p>Treatment of motion sickness</p> Signup and view all the answers

    Which of the following antihistamines is particularly noted for its antimuscarinic effects?

    <p>Promethazine</p> Signup and view all the answers

    Which statement regarding the pharmacokinetics of Hyoscine is accurate?

    <p>Transdermal delivery can provide therapeutic effects for 72 hours.</p> Signup and view all the answers

    What mechanism of action do antihistamines like Promethazine primarily use to prevent vomiting?

    <p>Antagonism at histamine H1 receptors</p> Signup and view all the answers

    What is a common side effect associated with the use of Promethazine?

    <p>Drowsiness</p> Signup and view all the answers

    Which medication is used specifically for chemotherapy-induced vomiting?

    <p>Metoclopramide</p> Signup and view all the answers

    What is the action of Betahistine (Betaserc) in treating vertigo?

    <p>H3 receptor antagonist</p> Signup and view all the answers

    What is one of the side effects of dopamine antagonists used for chemotherapy-induced vomiting?

    <p>Extra pyramidal side effects</p> Signup and view all the answers

    Which neurotransmitter is primarily involved in the mechanism of action for dopamine D2 antagonists?

    <p>Dopamine</p> Signup and view all the answers

    What is the main use of an anticholinergic drug such as Scopolamine?

    <p>Prophylaxis for motion sickness</p> Signup and view all the answers

    Which class of drugs includes Ondansetron and Granisetron?

    <p>5-HT3 antagonists</p> Signup and view all the answers

    What type of receptor antagonism is primarily targeted by the drug group that includes Tetrahydrocannabinol?

    <p>Cannabinoid receptors</p> Signup and view all the answers

    Which of the following is NOT a side effect associated with anticholinergics?

    <p>Increased appetite</p> Signup and view all the answers

    What is the primary mechanism of action of 5-HT3 antagonists?

    <p>Blocking serotonin receptors</p> Signup and view all the answers

    Which of the following uses the transdermal patch for delivery?

    <p>Scopolamine</p> Signup and view all the answers

    What is a common use for benzodiazepines such as Lorazepam in the context of vomiting?

    <p>Management of anxiety related to vomiting</p> Signup and view all the answers

    Which of the following statements about dopamine receptor antagonists is true?

    <p>They specifically reduce vomiting caused by chemotherapy.</p> Signup and view all the answers

    What is the primary mechanism of action for metoclopramide and domperidone?

    <p>Dopamine receptor antagonism and 5-HT4 agonism.</p> Signup and view all the answers

    Which of the following side effects is associated with the use of serotonin (5-HT3) antagonists?

    <p>GIT upset and constipation.</p> Signup and view all the answers

    What is a distinguishing characteristic of domperidone compared to metoclopramide?

    <p>Ability to be given rectally by suppository.</p> Signup and view all the answers

    Which of the following is an incorrect use of 5-HT3 receptor antagonists?

    <p>First trimester pregnancy nausea.</p> Signup and view all the answers

    Which drug is considered the most potent antiemetic among the options provided?

    <p>Ondansetron.</p> Signup and view all the answers

    Why might a physician choose to prescribe prochlorperazine for a patient experiencing motion sickness?

    <p>It has antimuscarinic activity.</p> Signup and view all the answers

    What major effect does stimulation of the 5-HT4 receptor have in the gastrointestinal tract?

    <p>Increased cholinergic activity.</p> Signup and view all the answers

    Which drug is effective as an adjuvant in chemotherapy-induced vomiting?

    <p>Nabilone</p> Signup and view all the answers

    What is a common side effect of cannabinoids like Nabilone?

    <p>Dizziness</p> Signup and view all the answers

    What is the mechanism of action for NK1 receptor antagonists like Aprepitant?

    <p>Blocking substance P activity</p> Signup and view all the answers

    Which of the following has a long half-life and is administered intravenously?

    <p>Palonosetron</p> Signup and view all the answers

    What does Aprepitant inhibit in relation to drug interactions?

    <p>CYP3A4</p> Signup and view all the answers

    Which corticosteroid is used effectively in acute emesis when combined with Ondansetron?

    <p>Dexamethasone</p> Signup and view all the answers

    Which of the following is NOT a common side effect of cannabinoids?

    <p>Hiccups</p> Signup and view all the answers

    What type of pharmacokinetic profile is associated with Granisetron?

    <p>Rapid oral absorption</p> Signup and view all the answers

    Study Notes

    Pharmacotherapy of GIT and Respiratory Disorders

    • Course title: Pharmacotherapy of GIT and Respiratory Disorders
    • Course code: RPB20403
    • Instructor: Dr. Omar AH

    Topic 1: Antiemetic Drugs

    • Learning Outcomes:
      • Pathophysiology of vomiting
      • Receptor antagonists
      • Antipsychotic drugs
      • Metoclopramide & domperidone
      • Cannabinoids
      • Steroids & neurokinin antagonists

    Definitions

    • Nausea: The immediate need to vomit, associated with gastric stasis
    • Retching: Making the sound and movement of vomiting before vomiting
    • Vomiting: Forceful expulsion of gastric contents
    • Peristalsis: Wave-like muscle contractions that move food through the digestive tract

    Antiemetics

    • Used to treat nausea and vomiting
    • Uncontrolled vomiting can cause dehydration, electrolyte imbalance, and aspiration pneumonia

    Etiology (Causes of Vomiting)

    • Gastrointestinal (GI) Disorders:
      • Gastroenteritis (viral, bacterial, or parasitic infections of the GI tract)
      • Food poisoning (ingestion of contaminated food or water)
      • Indigestion (overeating, excessive alcohol consumption, oily or spicy food)
      • Peptic ulcers (erosions in stomach or small intestine lining)
      • Gastritis (inflammation of stomach lining)
      • Gastroparesis (delayed emptying of stomach)
      • Intestinal obstruction (blockage of intestines)
      • Appendicitis (inflammation of appendix)
      • GERD (gastroesophageal reflux disease)
    • Other Conditions:
      • Motion sickness (disturbances of the middle ear)
      • Pregnancy (hormonal changes and increased pressure on the stomach)
      • Migraines (severe headaches)
      • Medications (side effects)
      • Neurological disorders (brain injuries, tumors, or infections)
      • Emotional distress (anxiety, stress, depression, sleep deprivation)
      • Toxic exposure (ingestion of poisons or toxins, or radiation exposure)
      • Metabolic disorders (liver or kidney disease)
      • Cancer
      • Surgery and pain

    Vomiting Symptoms

    • Sweating: Cold sweats
    • Salivation: Increased production of saliva
    • Dizziness: Feeling of lightheadedness or faintness
    • Pale skin: Loss of color in the skin
    • Headache: Pain in the head
    • Abdominal cramps: Stomach pain
    • Weakness: Fatigue or lack of energy
    • Loss of appetite: Reduced interest in eating
    • Dehydration: Fluid loss due to vomiting and diarrhea
    • Weight loss: Decreased body weight due to inability to keep food down
    • Tachycardia: Increased heart rate

    Vomiting Treatment Strategies

    • Pharmacological: Over-the-counter or prescription medications to stop vomiting
    • Non-pharmacological:
      • Hydration: Drink fluids (water, clear broth, or sports drinks)
      • Bland diet: Consume bland foods (toast, crackers, applesauce) avoiding spicy, greasy, or acidic foods
      • Rest, relaxation and fresh air

    Prevention of Vomiting

    • Avoid foods and drinks that trigger vomiting
    • Eat small, frequent meals (avoid overeating)
    • Eat a balanced diet with plenty of fruits, vegetables, and whole grains
    • Stay hydrated
    • Get enough rest and sleep, and fresh air
    • Avoid alcohol and caffeine
    • Take medications for motion sickness when traveling
    • Practice good food hygiene to prevent food poisoning
    • Manage stress using relaxation techniques

    Pathophysiology

    • Vomiting is a protective reflex in response to toxins, irritants, or stimuli affecting the CTZ or the vomiting center
    • The Vomiting center receives stimulatory signals from 4 pathways:
      • Chemoreceptor trigger zone (CTZ)
      • Vagal afferent neuron from GI system (Serotonin and Neurokinin receptors)
      • Central vestibular nuclei (inner ear)
      • Higher centers of the brain

    Drugs associated with a high incidence of nausea & vomiting

    (List of drugs and their associated symptoms)

    The Vomiting Cascade

    • Vomiting center stimulation
    • Relaxation of the lower esophageal sphincter
    • Contraction of diaphragm and abdominal muscles
    • Increased intra-abdominal pressure
    • Closed epiglottis
    • Vomiting occurs

    Receptor antagonist concept

    • Drugs selectively bind to receptors in the vomiting center of the brainstem
    • Block signaling pathways
    • Inhibit stimulation of the GI tract, diaphragm, and abdominal muscles

    Classes of Antiemetic drugs

    (List of drug classes and associated examples)

    Anticholinergics (Muscarinic receptor antagonist)

    • Examples: Hyoscine, Scopolamine, Dicyclomine
    • Mechanism: Act on muscarinic receptors in the visceral afferent pathways from the gut and labyrinth to the vomiting center
    • Use: Motion sickness prophylaxis, not for chemotherapy.
    • Side effects: Dry mouth, blurry vision, drowsiness

    Histamine-1 (H1) receptor antagonists

    • Examples: Promethazine, Meclizine, Cyclizine, Diphenhydramine, Dimenhydrinate.
    • Use: Motion sickness, morning sickness, pregnancy nausea
    • Side effects: Drowsiness, sedation, constipation, CNS depression, Headache, Dry mouth, urinary retention, blurry vision

    Dopamine antagonists (D2-RA).

    • Examples: Chlorpromazine, Haloperidol, Domperidone, Metoclopramide

    • Use: Chemotherapy, radiation vomiting.

    • Side effects: Sedation, hypotension, extra pyramidal effects, restlessness.

    Serotonin (5-HT3) antagonists

    • Examples: Ondansetron (Zofran), Granisetron, Palonosetron, Dolasetron.
    • Use: Chemotherapy-induced vomiting, Post-operative vomiting
    • Side effects: Headache, dizziness, GIT upset, constipation

    Neurokinin 1 (NK1) receptor antagonists

    • Examples: Aprepitant, fosaprepitant.
    • Use: Chemotherapy-induced vomiting

    Corticosteroids

    • Examples: Dexamethasone, Methylprednisolone
    • Use: acute emesis, often combined with other antiemetics
    • Side effects: Hyperglycemia, hypertension, cataract, osteoporosis, increased Intraocular pressure

    Adjuvant drugs (Prokinetics)

    • Use: Enhance coordinated GIT propulsive motility, helping relieve nausea and vomiting.
    • Examples: Metoclopramide, Domperidone

    Benzodiazepines & barbituates

    • Use: Reduce anticipatory vomiting related to anxiety

    Summary of therapeutic choices (for motion sickness, morning sickness, chemotherapy)

    • Provides specific drug options in each context noting the need to avoid certain drugs in early stages of pregnancy

    Chemotherapy-induced vomiting

    • Drugs: D2 receptor antagonists (Metoclopramide, Domperidone), 5HT3 receptor antagonists (Ondansetron), Adjunctive treatments (e.g. Benzodiazepines, Corticosteroids, Cannabinoids).
    • Other induced vomiting: Cytotoxic drugs, GI disorders, radiation
    • Postoperative vomiting
      • Drugs: Scopolamine, Metoclopramide, Domperidone, Prochlorperazine

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    Related Documents

    Pharmacotherapy of GIT and Respiratory Disorders RPB20403 PDF

    Description

    This quiz focuses on the pharmacotherapy of gastrointestinal and respiratory disorders, specifically related to antiemetic drugs. Explore the pathophysiology of vomiting, various receptor antagonists, and treatment options such as metoclopramide and cannabinoids. Test your knowledge on nausea, retching, and the etiologies of vomiting.

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