Anesthesia Considerations 

5-HT3 Receptor Antagonists 

 

Specific Drugs 

 

• Ondansetron = Gold standard 

  • 4 mg IV at the end of case 

  • NNT = 6 for prevention of vomiting & 7 for prevention of nausea 

• Granisetron 

  • 0.35-3 mg (5-20mcg/kg) IV  

  • As effective as ondansetron 

• Palonosetron 

  • 0.075 mg IV 

  • Effective for 24 hours & superior to ondansetron 4mg IV for PONV prevention 

• Ramosetron

  • 0.3 mg IV

  • Similar effectiveness to ondansetron

 

When to Administer 

 

• Ondansetron & Granisetron most effective when given at end of surgery 

• Palonosetron is usually given at the start of surgery 

 

Adverse Events

NNH listed is for Ondansetron 

• Constipation (NNH = 23) 

• ↑ Liver Enzymes (NNH = 31) 

• Headache (NNH = 36) 

• ↑ QTc: rare especially for 4mg Ondansetron IV dose 

 

Adapted from Anesth Analg. August 2020 - Volume 131 - Issue 2 - p 411-448