Which antiemetic combination is commonly used for pediatric chemotherapy‑induced nausea and vomiting?

• A. Serotonin receptor antagonists (ondansetron) plus corticosteroids (dexamethasone); NK1 antagonists (aprepitant) may be added for high emetogenic risk.
• B. Metoclopramide alone.
• C. Diphenhydramine alone.
• D. Ondansetron only, no steroids.

Answer: (A)

In pediatric chemotherapy-induced nausea and vomiting, using a serotonin receptor antagonist with a corticosteroid provides superior control because it hits two different pathways that drive nausea. The 5-HT3 receptor antagonist blocks serotonin signaling in the gut and brain’s vomiting centers, which is particularly important for the immediate, or acute, phase after chemo. Adding dexamethasone enhances antiemetic effects through additional mechanisms—reducing inflammation and broadening the overall suppression of nausea and vomiting. For regimens with high emetogenic risk, an NK1 receptor antagonist can be added to further block substance P signaling, improving control of both acute and delayed nausea.

That’s why the best approach is pairing a serotonin receptor antagonist like ondansetron with dexamethasone, and considering an NK1 antagonist for high-risk cases. Metoclopramide alone isn’t as effective and carries extrapyramidal side effects; diphenhydramine alone doesn’t provide adequate antiemetic protection for chemotherapy; ondansetron alone lacks the added benefit of corticosteroid therapy.