Overview
NK1 receptor antagonist for chemotherapy-induced nausea. Often combined with 5-HT3 antagonist and dexamethasone. CYP3A4 substrate and moderate inhibitor.
Dosing
Chemo: 125mg PO day1, 80mg days2-3 PO: 1h before chemo Max dose: 125mg/day
Pharmacokinetics
Onset: 1-2h Peak: 4h Duration: 24h Metabolism: Hepatic CYP3A4 Elimination: Fecal Half-life: 9-13h
Pharmacodynamics
Mechanism: Substance P/NK1 blockade Effects: - Delayed-phase antiemetic - Few EPS - CYP3A4 interactions - Fatigue
Clinical Considerations
Clinical Pearls: 1. Combine with ondansetron/dexamethasone 2. Give before highly emetogenic chemo 3. Many drug interactions 4. Capsules not for liquid prep 5. Expensive 6. Alternative to olanzapine 7. Monitor warfarin levels 8. Store at room temperature