Anti-Emetics

• As from https://emcrit.org/ibcc/antiemetic

Before Starting Treatment

• See Nausea and Vomiting
• Identify, treat or remove cause if possible
• Gastrointestinal
  • Obstruction (e.g. intestinal obstruction, gastric outlet obstruction)
  • Hypomotility (e.g. gastroparesis, ileus)
  • Acute gastroenteritis
  • Pancreatitis
  • Mesenteric ischemia
  • Appendicitis, cholecystitis
  • Constipation
• Central Nervous System
• Ear and labyrinthine disorders (often associated with vertigo)
  • Vestibular neuronitis
  • Meniere’s disease
  • Otitis media
• Intracranial pressure elevation
• Migraine
• Cyclic vomiting syndrome, cannabinoid hyperemesis syndrome
• Medications which may cause nausea
  • Chemotherapy
  • Analgesics
    • Aspirin
    • NSAIDs
    • Opioids
  • Anesthetic agents
  • Antibiotics
    • Erythromycin
    • Sulfonamides
    • Acyclovir
• Cardiovascular
  • Antiarrhythmics
  • Antihypertensives (beta-blockers, calcium channel blockers)
  • Digoxin
  • Diuretics
• Endocrine
  • Oral contraception
  • Oral antidiabetic agents
• Neurology
  • Anticonvulsants
  • Parkinson’s disease medications (dopaminergic)
• Other/Metabolic
  • Pregnancy (hyperemesis gravidarum; generally within the first nine weeks of pregnancy)
  • Uremia
  • Fulminant hepatic failure
  • Ketoacidosis (e.g., diabetic ketoacidosis)
  • Hypercalcemia
  • Hyperthyroidism
  • Addison’s disease
  • Myocardial ischemia (anginal equivalent)

5-$\mathrm{HT}{}_3$ Receptor Antagonists

• Indication: general use with particular use in acute gastroenteritis
• Ondansetron 4-8mg IV/PO 8-12 hourly

Dopamine Antagonists

• EPSE (acute dystonic reactions) are more common in the elderly and people <20 years
• EPSE is rarer with domperidone
• Domperidone and metoclopramide have prokinetic activity which may be useful in gastroparesis
• Metoclopramide 10mg IV/IM/PO 8-hourly
  • Particular use in migraine or acute gastroenteritis
  • Avoid use in patients younger than 20 years and older persons—acute dystonic reactions are more common in young adults and older persons
  • Can cause extrapyramidal adverse effects—avoid in Parkinson disease
  • Can cause irreversible tardive dyskinesia
  • Do not use for longer than 5 days
  • Avoid if stimulation of the gastrointestinal tract is dangerous (eg gastrointestinal obstruction or perforation)
• Prochlorperazine 20mg PO first dose then 10mg PO 2 hours later then 5-10mg PO 8-hourly
  • General use, particularly for nausea and vomiting associated with migraine, motion sickness or acute gastroenteritis
  • Can cause sedation, prolongation of the QT interval and extrapyramidal adverse effects, including tardive dyskinesia and akathisia; avoid in Parkinson disease
  • Can have anticholinergic effects
• Droperidol is often used for prevent PONV 0.25-0.625 mg IM as a single dose
  • Mostly limited use with particular use for opioid induced nausea and vomiting and anxious or agitated patients
  • Has a long duration of action and counteracts adverse opioid effects
  • Can cause sedation and EPS; avoid in Parkinsons

Sedating Antihistamines

• Promethazine 25mg orally every 4-6 hours (max 100 mg in 24 hours)
  • General use, with particular use in motion sickness
  • Can cause sedation, lower the seizure threshold and have anticholinergic effects
  • Can cause extrapyramidal adverse effects, including tardive dyskinesia; avoid in Parkinson disease
• Cyclizine for motion sickness

Anticholinergics

• Hyoscine hydrobromide can be used prevent motion sickness

Substance P Antagonists

• Aprepitant, fosaprepitant, fosnetupitant and netupitant are used with a 5HT3 antagonist and dexamethasone to prevent nausea and vomiting with highly or moderately emetogenic chemotherapy

Corticosteroids

• Dexamethasone is used to prevent
  • Limited use with PONV and as adjunctive treatment in chemotherapy-induced nausea and vomiting or with bowel obstruction or raised intracranial pressure
  • May cause mood or sleep disturbance; other adverse effects are unlikely with a single dose
  • Use with caution in sepsis, haematological malignancy and diabetes

Sources

• eTG Article: Antiemetic drugs in adults
• AMH Online: Nausea and Vomiting