Chemotherapy-induced Nausea and Vomiting

Introduction to Treatment Recommendations

• The American Society of Clinical Oncology recommends ondansetron monotherapy for low-emetic-risk chemotherapy, ondansetron + dexamethasone for moderate-emetic-risk chemotherapy, and ondansetron + dexamethasone + aprepitant for high-emetic-risk chemotherapy 1, 2
• The following table summarizes the recommended antiemetic regimens based on emetogenic risk:

1

Administration and Dosage

• Ondansetron may be administered orally for mild-moderate vomiting in outpatient settings, or IV/IM for moderate-severe vomiting or when oral intake is not tolerated, as recommended by the Clinical Infectious Diseases guidelines 3
• The recommended dose for pediatric patients with moderate to severe vomiting is 0.15 mg/kg IV (maximum 16 mg), and for pediatric patients receiving chemotherapy, the recommended dose of ondansetron is 0.15 mg/kg IV (maximum 8 mg per dose) 4, 1
• Higher weight-based doses of 5-HT3 antagonists may be required in children compared to adults due to differences in pharmacokinetics, as stated by the American Society of Clinical Oncology 5
• Granisetron can be considered as an alternative 5-HT3 antagonist at a dose of 40 μg/kg IV, and may require higher weight-based dosing in pediatric patients, as suggested by the American Society of Clinical Oncology 5

Safety and Efficacy

• Ondansetron has been shown to effectively reduce vomiting episodes and decrease the need for IV hydration and hospitalization in pediatric patients, with evidence supporting its superior efficacy compared to other antiemetics like metoclopramide and chlorpromazine 4
• Ondansetron is significantly more effective than metoclopramide and chlorpromazine (both combined with dexamethasone) in reducing nausea and vomiting in children, with the combination of ondansetron and dexamethasone improving antiemetic efficacy compared to either agent alone 1
• The safety and efficacy of oral ondansetron have not been established in pediatric patients for the prevention of nausea and vomiting associated with highly emetogenic chemotherapy, radiation therapy, or postoperative nausea and vomiting 1
• Ondansetron effectively reduces vomiting episodes, decreases the need for IV hydration and hospitalization, but may increase diarrhea episodes in the 48 hours following administration 4

Special Considerations

• Patients with congenital long QT syndrome or those taking other medications that prolong the QT interval should be monitored for QT interval prolongation 1, 4
• In patients with severe hepatic impairment, the total daily dose should not exceed 8 mg, and no dose adjustment is recommended for patients with any degree of renal impairment 1
• The American Society of Clinical Oncology recommends monitoring ECG in patients with electrolyte abnormalities, congestive heart failure, bradyarrhythmias, or those taking other QT-prolonging medications, due to the risk of QT prolongation associated with ondansetron 1
• The Clinical Infectious Diseases guidelines emphasize the importance of not delaying hydration, as antiemetics are not a substitute for appropriate fluid and electrolyte therapy 3
• The Clinical Infectious Diseases guidelines advise against using antimotility drugs, such as loperamide, in children <18 years with acute diarrhea 3