Nausea & Vomiting

Nausea & Vomiting – Michael J. Neuss

General Approach:

  • VOMIT mnemonic (see below)
  • Several antiemetics can prolong QT interval (see below). Caution is advised when QTc is prolonged (>450 in men and >470 in women), particularly if hypokalemia, hypomagnesemia, or if taking multiple medications with QT prolonging effects.
  • Consider drug use and withdrawal, medication effects, cardiac ischemia, pregnancy, abdominal pathology, adrenal insufficiency, CNS lesion, anxiety, severe pain
  • Labs: BMP, hepatic functional panel, lactate, amylase/lipase, TSH, cortisol (AM vs cort stim), troponin, β hCG, U/A, UDS
  • EKG (know QT, eval for ischemia), KUB/upright, Small bowel follow-through (SBFT)
  • CT A/P, CNS imaging (CT vs MRI; eval for mets in oncology pts)
  • EGD has limited utility unless mechanical gastric outlet obstruction is suspected





Vestibular &


Labyrinthitis, Vestibular neuritis, Meniere’s disease

Cerebellar stroke

- Scopolamine, diphenhydramine

- Check for nystagmus, truncal ataxia, focal deficits; consider CNS imaging if high risk

- VUMC: consider referral to Pi β Phi for vertigo


Adhesions, hernia, volvulus,  constipation

Gastric outlet obstruction (pyloric stenosis from malignancy or PUD)

- Bowel Obstruction: KUB (about 80% sensitive) vs. CT A/P,  Surgical consultation (general surgery at VA and EGS at VUMC)

- SBFT – both diagnostic and therapeutic

- Bowel rest, NGT (if tolerated/indicated), bowel regimen

- Gastric outlet obstruction: Inflammation may respond to acid suppression and NGT to suction

- Endoscopic dilation, surgery or stenting



Gastroparesis, autonomic dysfunction (e.g. in diabetics)

- If GERD, trial of PPI and de-escalate to H2 blocker once able

- Metoclopramide (caution due to side effects, erythromycin second line)

- Consider gastric emptying study (limited sensitivity & specificity ONLY outpt off narcotics)

- Consider autonomics evaluation


Antibiotics, SSRI,  Opioids cannabinoid hyperemesis

- UDS, CSMD search

- Careful med review

- Ondansetron

- Cannabinoid hyperemesis syndrome:  hot showers cyclically. Stop cannabis

Inflammation or Infection

Gastroenteritis, PUD, hepatitis, pyelonephritis, nephrolithiasis, cholecystitis, pancreatitis

- Ondansetron, other agents acceptable

- Treat underlying problem


Uremia, ketoacidosis, hypercalcemia,


- Ondansetron, others acceptable

- Treat underlying problem

- Pre-treatment for chemo ( usually part of chemo order sets)





Med (by class)


Side effects?


Serotonin antagonists




Ondansetron (Zofran)

4-8mg PO/IV q6h

Constipation, headache





2 mg PO x1, 1 mg PO BID pre-chemo, daily patch, OR 10mcg/kg pre-chemo



Dopamine antagonists




Prochlorperazine (Compazine)

5-10 mg PO q6h, 2.5 – 10 mg IV q6h, 25 mg PR q6h

EPS, less sedation than





0.5-1 mg PO/IV q6h



Zyprexa (Olanzapine)2

2.5-10mg PO q6H



Metoclopramide (Reglan)

10 mg PO/IV q6h

EPS, dystonia, tardive dyskinesia








0.5-2mg PO; 0.25 – 1 mg IV q6h

Sedation, delirium






Promethazine (Phenergan)

12.5 - 25mg PO/IV q6h OR 25 mg PR q6h

Sedation, EPS (DA antagonist as well)


Diphenhydramine (Benadryl)

25-50mg PO/IV q6h

Sedation, delirium, urinary retention, ileus




25 – 50 mg PO qday







Scopolamine (Hyoscine)

1.5 mg patch q3day







Dexamethasone (Decadron)3

20 mg PO or IV for CINV; can give with Ondansetron 8-18 mg or Granisetron 10mcg/kg IV or 2 mg PO if high severity CINV

Hyperglycemia, fluid retention