How to treat acute cyclical vomiting syndrome in the emergency department (ED) that is unresponsive to ondansetron (Zofran)?

Management of Cyclic Vomiting Syndrome Unresponsive to Ondansetron in the ED

For cyclic vomiting syndrome (CVS) episodes unresponsive to ondansetron in the emergency department, administer sumatriptan (nasal spray or subcutaneous injection) as the most effective rescue therapy, combined with aggressive IV hydration using dextrose-containing fluids and benzodiazepines for sedation. 1

First-Line Interventions

1. Environment Management

   • Place patient in a dark, quiet room
   • Allow hot water bathing/showering if requested (effective in 48% of non-cannabis using CVS patients) 1

2. Aggressive IV Hydration

   • Administer 10-20 mL/kg bolus of dextrose-containing fluids (10% dextrose in normal saline)
   • Follow with maintenance IV fluids 1
   • Replace electrolytes as needed based on laboratory results

3. Pharmacological Management for Refractory Vomiting

   • Sumatriptan

     • Administer as nasal spray or subcutaneous injection
     • Most effective when given early in the episode
     • Complete response in 30-50% of CVS episodes 1
     • Contraindicated in patients with ischemic vascular conditions, vasospastic coronary disease, and uncontrolled hypertension 1

   • Benzodiazepines

     • Lorazepam 0.5-2 mg IV every 4-6 hours
     • Provides sedation and anxiety reduction
     • Midazolam can be considered as continuous low-dose IV infusion for refractory cases 2

   • Neuroleptics for Severe Cases

     • Haloperidol 0.5-2 mg IV every 4-6 hours for refractory vomiting 1
     • Olanzapine 5-10 mg PO for breakthrough nausea and vomiting 1

Second-Line Options for Refractory Cases

1. Aprepitant/Fosaprepitant

   • Aprepitant 125 mg day 1,80 mg days 2-3 1
   • Fosaprepitant 150 mg IV (single dose) for severe cases 3
   • Has shown dramatic response in case reports of severe CVS 4

2. Clonidine

   • Consider IV clonidine in combination with midazolam for refractory cases
   • May reduce episode duration from 4-5 days to 16-48 hours 2

3. Metoclopramide

   • 10-20 mg IV every 6 hours for intractable vomiting 1
   • Monitor for akathisia and extrapyramidal side effects

Supportive Care

• Correct electrolyte abnormalities
• Avoid opioids as they may worsen nausea and carry addiction risk 1
• Consider IV dextrose-containing fluids even in non-hypoglycemic patients, as this may help break the cycle 1

Important Considerations

• Early intervention is critical - delayed treatment may worsen outcomes and prolong episodes 1
• Rule out cannabinoid hyperemesis syndrome in patients with cannabis use (requires cessation for 6 months or 3 typical cycle lengths to definitively rule out) 1
• Avoid antimotility agents like loperamide in children <18 years of age with acute diarrhea 5
• Identify triggers for future prevention (stress, certain foods, sleep deprivation) 1

Discharge Planning

• Consider prophylactic treatment for frequent episodes:

  • Tricyclic antidepressants (first-line for adults and children ≥5 years)
  • Cyproheptadine for children <5 years
  • Beta-blockers like propranolol (especially effective in children) 1

• Risk factors for non-response to standard therapy include:

  • Co-existing migraine headache
  • Psychiatric disorders
  • Chronic narcotic and marijuana use 6

By implementing this stepwise approach with early intervention focused on sumatriptan, aggressive hydration, and appropriate sedation, most CVS episodes can be effectively managed even when initially unresponsive to ondansetron.