nausea

Introduction

An unpleasant, but not painful sensation generally perceived in the upper abdomen.

It is generally accompanied by hypersalivation & the desire to vomit or the feeling that vomiting is imminent.

It may be brief, prolonged & sometimes occurs in waves.

See vomiting.

Etiology

• gut wall dilation -constipation, bowel obstruction, ileus (GUT)*
• gut mucosal injury
  • radiation therapy, chemotherapy, infection, inflammation (gastritis), direct tumor invasion (GUT)*
• drugs, metabolites, bacterial toxins (CTZ)*
  • new narcotic use is a likely cause of nausea
• motion sickess, labyrinthine disorders (vesibular)*
• anticipatory nausea (cerebral cortex)*
• increased intracranial pressure (?)*

* see pathology for mechanism at site or origin

Pathology

• mediated by
  • dopamine D2 receptors or 5-HT3 receptors in GI tract
  • dopamine D2 receptors, 5-HT3 receptors or neurokinin-1 receptors in the chemoreceptor trigger zone (CTZ)
  • histamine H1 receptors & muscarinic receptors in the vestibular system
  • unknown mediators in the cerebral cortex (putative)

Management

• sucking of hard candy or popsicle especially in children
• anticholinergics for motion sickness - scopolamine
• antihistamines - inner ear dysfunction or motion sickness
  • dimenhydrinate (Dramamine) 50 mg PO/IV/IM every 4 hours
  • promethazine (Phenergan) 25-50 mg PO/IV/IM every 4-6 hours
• dopaminergic antagonist (metochlopramide, prochlorperazine, haloperidol) for dopamine D2 receptor mediated nausea
• antacids for nausea due to gastritis
• serotonin antagonists (ondansetron, granisetron) for 5-HT3 receptor (chemotherapy) mediated nausea
• aprepitant for resistant chemotherapy-induced nausea
• benzodiazepines for anticipitory nausea
• glucocorticoids for increased intracranial pressure
• octreotide for nausea due to bowel obstruction
• do not use topical agents for treatment of nausea
• treatment of nausea in palliative care
  • if due to constipation, bowel obstruction, ileus
    • dopaminergic antagonists
      • metoclopramide, prochlorperazine, haloperidol, olanzapine
      • olanzapine improves chronic nausea in patients with advanced incurable cancer
  • if due to chemotherapy, radiation, inflammation, advanced incurable cancer
    • ondansetron, granisetron
    • if intractable nausea & vomiting use ondanstetron 4 mg every 8 hours around the clock
    • ondansetron contraindicated wiht allergy to another 5-HT3 antagonist. i.e. alosetron
  • if due to drugs, metabolites, bacterial toxins
    • dopaminergic antagonists, glucocorticoids, serotonin receptor antagonists
    • neurokinin-1 receptor antagonists: aprepitant, netupitant
    • aprepitant relies on CYP3A4 metabolism as does oxycodone
  • if due to labyrinthine disorder, motion sickness
    • anticholinergic agents: scopolamine, diphenhydraine, promethazine
  • increased intracranial pressure: glucocorticoids
• also see vomiting

More general terms

• sign/symptom

More specific terms

• nausea/vomiting - chemotherapy induced
• post-operative nausea & vomiting

Additional terms

• vomiting

Patient information

nausea patient information