Associated with adverse drug interactions - nausea

Red flags

Nausea preceding an important toxic ingestion (paracetamol, digoxin, theophylline) - do not dismiss as isolated
Nausea + visual disturbance (xanthopsia, halos) - digoxin toxicity
Nausea + tinnitus + hyperventilation - salicylate toxicity
Persistent vomiting risking aspiration in reduced consciousness

Chemoreceptor trigger zone stimulation

Opioids (common, often transient), digoxin toxicity, dopamine agonists, chemotherapy

Direct gastric irritation

NSAIDs, iron, antibiotics (esp. macrolides, metronidazole), metformin, bisphosphonates

Vestibular

Metabolic/toxic

Digoxin toxicity (classic early feature), theophylline toxicity, salicylate toxicity, chemotherapy-induced (highly emetogenic agents - cisplatin)

Withdrawal

Timing relative to dose/new drug
Associated symptoms pointing to a specific toxin (visual change, tinnitus, palpitations)
Chemotherapy regimen and emetogenic risk category

Address the underlying cause/causative drug where possible
Ondansetron first-line for most drug-induced nausea; avoid metoclopramide/prochlorperazine in Parkinson's disease or with concurrent dopamine antagonists (extrapyramidal risk)
Chemotherapy - risk-stratified prophylaxis (5-HT3 antagonist + dexamethasone +/- NK1 antagonist for highly emetogenic regimens)
Opioid-induced - usually settles within days; antiemetic cover during initiation, dose reduction/rotation if persistent

Isolated nausea can be the only early warning of a serious ingestion - keep a low threshold to check levels (paracetamol, digoxin, salicylate)
Metoclopramide is a common precipitant of acute dystonia/parkinsonism, especially in the young and in Parkinson's disease
Chemotherapy antiemetic prophylaxis undertreated relative to actual emetogenic risk category is a preventable cause of poor QoL

"Nausea alone doesn't get dismissed - I match it against the drug list for anything that needs a level checked."

7 more sections, plus exam facts

Premium unlocks every note across every specialty, and the full exam fact library behind it.