Nausea and Vomiting Quiz

Course Information

• Course name: PHARM 345
• Course topic: Nausea and Vomiting
• Instructor: Dr. Rene Breault
• Semester: Winter 2025
• Credits: Not specified
• Resources: DiPiro JT, CPHA, Mahmoud

Learning Objectives

• Describe the etiology and pathophysiology of nausea and vomiting (NV).
• Compare and contrast non-pharmacological and pharmacological options for NV.
• Assess patients with nausea or vomiting symptoms and develop a treatment plan.
• Identify when to refer patients with NV to another healthcare provider.
• Develop a suitable monitoring plan for NV management (parameters for efficacy/safety and timelines).
• Provide appropriate education for patients with motion sickness, pregnancy-related NV, postoperative NV (PONV), antineoplastic-induced NV, and NV in children, taking into consideration etiology, patient factors, comorbidities, and potential drug interactions.

Resources

• Chapter 53: Nausea and vomiting (DiPiro JT, 12th edition)
• Chapter: Nausea and vomiting (CPHA, Therapeutic Choices CPS)
• Chapter 6: Nausea and vomiting (Mahmoud, Patient Assessment in Clinical Pharmacy)

Case Study: Natalie

• Natalie is a 32-year-old pregnant woman (10 weeks) experiencing nausea for 4 weeks.
• Reports no dizziness, lightheadedness, or diarrhea.
• Lost approximately 1 kg in recent weeks.
• Nausea somewhat relieved by eating salty foods.
• Wants help for her nausea.

What is Nausea and Vomiting?

• Nausea: Subjective feeling of impending vomiting or need to vomit.
• Retching: Spasmodic contractions of the diaphragm and intercostal muscles, epiglottis closed.
• Vomiting (emesis): Forceful oral expulsion of gastric contents, GI retroperistalsis, often associated with pallor, tachycardia, and diaphoresis. It's different from regurgitation, as contents rise to the pharynx but not with forceful ejection.

How Vomiting Happens

• Vomiting is triggered by afferent impulses to the Vomiting Center (VC) or Emetic Center (EC).
• VC contracts the diaphragm and abdominal muscles.
• Lower esophageal sphincter relaxes.
• Peristalsis reverses direction, pushing stomach contents out of the mouth.
• Soft palate is raised to prevent GI contents from entering the nasopharynx.
• Epiglottis closes to prevent pulmonary aspiration.

Afferent Impulses (Stimuli)

• Chemical signals: Drugs, toxins, or metabolic disturbances (e.g., hypercalcemia, uremia) stimulate the chemoreceptor trigger zone (CTZ).
• Visceral signals: GI tract irritation or distension.
• Vestibular input: Motion sickness or inner ear disturbances stimulate vestibular nuclei.
• Cortical input: Anxiety, fear, disgust, and sensory inputs like bad smells or sights.

Pathophysiology

• Emetic reflex involves multiple receptors (Serotonin [5-HT₃], Dopamine [D₂], Acetylcholine [Ach, muscarinic, M₁], Histamine [H₁], Neurokinin-1 [NK-1], Cannabinoid [CB₁], Opioid).
• VC receives afferent impulses from different areas (Medulla Oblongata, Area postrema, Cerebral Cortex, Thalamus, Hypothalamus, Vestibular Apparatus, Ear, Visceral Afferents).

Etiology - Causes of Nausea and Vomiting

• Motion sickness
• Nausea and vomiting of pregnancy (NVP)
• Postoperative nausea and vomiting (PONV)
• Antineoplastic induced nausea and vomiting (AINV)
• Infections (gastroenteritis)
• Cardiac
• Gastrointestinal
• Metabolic/endocrine causes
• Central Nervous System
• Psychiatric

Complications of Vomiting

• Fluid, electrolyte, and metabolic alterations (dehydration, hypotension, hemoconcentration, oliguria, muscle weakness, electrolyte abnormalities, cardiac arrhythmias).
• Aspiration pneumonia
• Prolonged vomiting (nutritional deficiencies, malnutrition, esophagitis, lacerations at the gastroesophageal junction, multiple purpuric lesions, dental caries/erosions).

Approach to Nausea and Vomiting (NV)

• Three-step approach: Recognize and correct consequences of vomiting, identify underlying cause, treat/manage cause.
• Goals of therapy include preventing/halting nausea/vomiting, preventing complications (e.g., dehydration), and improving quality of life.
• Additional goals may vary depending on the cause.
• Patient assessment for signs/symptoms, medical history, social history, medications, allergies, physical exam, rule out red flags (signs/symptoms of significant dehydration or needing further medical attention)

Scholar Mnemonic for Symptom-Assessment

• S ymptom: What are the main symptoms?
• C haracteristic: What are symptoms like?
• H istory: What has happened in the past?
• O nset: When did it start?
• L ocation: Where is the problem?
• A ggravating Factors: What makes it worse?
• R emitting Factors: What makes it better?

Assessment of NV: Physical Exam and Red Flags

Types of physical examination, signs of dehydration, abdominal examination, neurologic examination, signs of psychiatric cause, general examination/diagnostic tests, complications, pregnancy test.

• Prompt evaluation for red flags, may need aggressive rehydration with IV fluids. Severe pain, abdominal issues, blood (or "coffee-grounds") in the vomitus or stool (black or tarry).
• Other considerations for referral, difficulty swallowing, age >55, weight loss, and signs/symptoms of prolonged vomiting

Treatment Approaches

• Determine the cause and severity of symptoms.
• Assess patient ability to swallow oral formulations.
• Consider and evaluate previous treatment attempts.
• Utilize non-pharmacological therapies: adequate hydration, avoiding noxious odors/foods, eating frequent small meals, reducing physical activity, positioning for labyrinth changes.
• Utilize appropriate pharmacological treatments

Non-Pharmacological Therapy

• Detailed treatment options for different types of nausea and vomiting, including acupressure, acupressure wristbands, and natural health products such as ginger, vitamin B6 , peppermint oil, green tea, and lemon balm.

Antiemetics Overview

• Antiemetic mechanism and pharmacology. Antiemetics involve blocking receptors (histamine, dopamine, serotonin, neurokinin).
• Detailed information on receptor antagonists (histamine, muscarinic, dopamine, serotonin, neurokinin). Types of medications and side effects covered. Include specific examples.
• Recommendations on treatment approaches for specific cases like pregnancy related NV and Post-Operative Vomiting (PONV) and Antineoplastic-induced NV (AINV).

Nausea/Vomiting of Pregnancy(NVP)

• Common in the first trimester (75% of women).
• Severity varies among patients, with average onset around 4 weeks, peaking at 9 weeks, and usually resolving by week 20.
• May be related to high estrogen levels, and associated with hCG (human chorionic gonadotropin)
• Hyperemesis gravidarum is a severe form and requires hospitalization, Non-pharmacological (diet modification, fluids, acupressure, and ginger) and pharmacological therapies (diclectin, pyridoxine, etc)
• Health Canada updated its monograph for ondansetron use in pregnancy which is no longer recommended.

Postoperative Nausea and Vomiting (PONV)

• Occurs in 25-30% of patients undergoing anesthesia.
• Risks are increased by factors like female, nonsmokers, and history of PONV/motion sickness, post-operative opioid use.
• Other risk factors may be the type of surgery and anesthesia, including nitrous oxide, or volatile anesthetics, use of general vs local anesthesia and anesthetic time, specific surgeries like abdominal, gynecologic, or eye surgeries, increased risk factors post-operatively.
• Prophylaxis of PONV.

Antineoplastic Induced Nausea and Vomiting (AINV)

• Classification of acute and delayed AINV.
• Emetic risk categorization for antineoplastic agents.
• Other factors affecting the risk of AINV (biological sex, past alcohol consumption, history of motion sickness/NVP, age, previous AINV).
• Pathogenesis of AINV (neurotransmitter receptors in VC, CTZ, and GIT).
• Prophylaxis of acute and delayed AINV; regimens for high and moderately emetic chemo.

Treatment of Breakthrough and Anticipatory AINV

• Treatment approaches, first line options such as metoclopramide, prochlorperazine, olanzapine and others like nabilone. Consider drug interactions for all
• Treatment for anticipatory AINV; use of benzodiazepines (lorazepam) and other behavioral therapies to prevent anticipatory nausea and vomiting.

Nausea and Vomiting in Children

• Most common cause is viral gastroenteritis, and the natural course includes preventing dehydration and electrolyte imbalance using oral rehydration solutions (ORS).

Role of the Pharmacist

• Assess patients, focusing on the cause, knowing when to refer, and treating the underlying cause when appropriate. Utilize pharmacological and non-pharmacological treatment modalities. Monitor and follow up with patients.

Case Study: Natalie

• What to assess in a patient like Natalie.

Case Study: Natalie - Recommendations

• Personalized recommendations for Natalie's situation.