Nausea & Vomiting

ABCs

urgent surgical review

escalation

surgery now: suspected bowel obstruction or perforation, peritonitis
bowel obstruction: nil by mouth, IV fluids, correct electrolytes; NG decompression if significant vomiting, marked distension, or high-grade obstruction: not routine
senior: new neuro sign or severe headache (raised ICP: image only when signs support it), or refractory vomiting with electrolyte derangement
GI: hematemesis → GI bleed; vomiting persisting despite treating the cause
shock / persistent dehydration despite fluids, suspected DKA / metabolic cause, pregnancy-related emergency, toxic ingestion, or PO intolerance after appropriate treatment → escalate

vomiting characteristics: content (food, bilious, feculent, blood); amount; relation to meals
associated symptoms: abdominal pain, fever, last bowel motion / flatus, distention
relevant history
- GI: prior disease, obstruction; renal: uremia, ESRD
- cardiac: IHD, AF; endocrine: diabetes (DKA risk)
- neuro: head trauma, headache, neck stiffness, photophobia, vertigo, weakness / numbness
examination
- bowel sounds: normal every 5–10 sec; ↓ / absent → ileus / obstruction; ↑ → gastroenteritis
- look for distention, tenderness; neuro exam if indicated

investigations
- baseline: VBG, RFT → correct electrolytes
- if unwell: CBC, VBG, LFT, RFT, Hs-Troponin, amylase, lipase, lactate, ECG; X-ray KUB if obstruction suspected
targeted workup (by suspicion)
- UTI / pyelonephritis: urine R/M, C/S, CRP, PCT; consider imaging + antibiotics
- cholecystitis: CBC, LFT, ultrasound abdomen, surgical consult
- pancreatitis: amylase, lipase, ultrasound; moderate hydration (avoid over-resuscitation, WATERFALL) + analgesia; oral feeding within 24–48 hr, not routine NPO → abdominal pain
- DKA: manage per protocol → hyperglycemia
- female (reproductive age): pregnancy test
- elderly / diabetic: ECG + Hs-Troponin (silent ischemia)

initial
- IV fluids if dehydrated / not tolerating PO; adjust for RBS; correct K, Mg, acid-base abnormalities as clinically indicated: no fixed target for every patient
- shock persisting despite fluids → Advanced: Shock
medications
- PPI: omeprazole (Losec) 20–40 mg IV OD: only if reflux, ulcer, or GI bleed suspected, not routine for undifferentiated vomiting
- no single preferred antiemetic: choose by cause, contraindications, QT/EPS risk
  - ondansetron 4–8 mg IV STAT: check ECG/QTc; caution with congenital long QT, heart failure, bradyarrhythmia, electrolyte derangement, other QT-prolonging drugs; max single IV dose 16 mg
  - metoclopramide 10 mg IV/PO TDS: avoid in obstruction, perforation, Parkinson’s; reduce dose in renal impairment
    - FDA boxed warning, tardive dyskinesia: max 5 days
  - cyclizine 50 mg PO/IM/slow IV, up to TDS: anticholinergic: caution in elderly, glaucoma, prostatic hypertrophy
- pregnancy: separate uncomplicated NVP from hyperemesis gravidarum (weight loss, ketosis, dehydration, electrolyte derangement)
  - first-line: pyridoxine (B6) 10–25 mg ± doxylamine; second-line: metoclopramide, ondansetron
  - thiamine before dextrose in prolonged vomiting / malnutrition risk: glucose without thiamine can precipitate Wernicke encephalopathy

source	type
FDA ondansetron QT safety communications	regulatory / safety update
FDA metoclopramide tardive dyskinesia boxed warning	regulatory / safety update
Thiamine-before-dextrose, hyperemesis gravidarum literature	evidence review
ACG / AGA acute pancreatitis guidance	international guideline

Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.

free the on-call checklist covers the whole shift on one printable page.

studying for the IM exam? the IM Rapid Review covers this in the same format. see the sample chapter.

reviewed Jul 2026updated Sep 2026file complaint/nausea-and-vomiting