dexamethasone + fosaprepitant + palonosetron

This is a triple-drug antiemetic regimen consisting of dexamethasone, fosaprepitant, and palonosetron. It is used primarily for the prevention of acute and delayed nausea and vomiting associated with highly or moderately emetogenic cancer chemotherapy. - **Dexamethasone** is a synthetic glucocorticoid corticosteroid that exerts anti-inflammatory and immunosuppressant effects; its precise antiemetic mechanism is not fully understood but may involve inhibition of prostaglandin synthesis and reduction in serotonin turnover in the central nervous system. - **Fosaprepitant** is a prodrug of aprepitant, acting as a selective antagonist of the neurokinin 1 (NK1) receptor, thereby blocking substance P-mediated emetic signaling in the brain. - **Palonosetron** is a second-generation serotonin 5-hydroxytryptamine type 3 (5-HT3) receptor antagonist with high binding affinity and long half-life, preventing both acute and delayed phases of chemotherapy-induced nausea by inhibiting serotonergic signaling from the gastrointestinal tract to the central nervous system[2][3][5]. This combination targets multiple pathways involved in emesis—serotonergic (acute phase), neurokinin/substance P (delayed phase), and corticosteroid-responsive mechanisms—providing superior prophylaxis compared to single or dual-agent regimens[2][3][5].