Aprepitant Dosing for Chemotherapy-Induced Nausea and Vomiting
Standard Oral Dosing Regimen
- The National Comprehensive Cancer Network recommends administering oral aprepitant 125 mg on Day 1 (one hour before chemotherapy) followed by 80 mg once daily on Days 2 and 3 for preventing chemotherapy-induced nausea and vomiting 1, 2
Intravenous Alternative (Fosaprepitant)
- The National Comprehensive Cancer Network suggests two IV dosing options: Fosaprepitant 115 mg IV on Day 1 only (30 minutes before chemotherapy), followed by oral aprepitant 80 mg on Days 2-3, or a single-dose regimen of Fosaprepitant 150 mg IV on Day 1 only 1, 2, 3
- A randomized study demonstrated that the single 150 mg IV dose was noninferior to the standard 3-day oral regimen 1, 3
Combination Therapy Requirements
- The National Comprehensive Cancer Network recommends that aprepitant be combined with a 5-HT3 antagonist (such as ondansetron, granisetron, dolasetron, or palonosetron) on Day 1 and dexamethasone 12 mg on Day 1, with continuation on subsequent days 1, 2, 4
- When aprepitant is used with dexamethasone, the dexamethasone dose should be reduced by approximately 50% due to CYP3A4 inhibition by aprepitant 1, 5
Efficacy by Chemotherapy Type
- For highly emetogenic chemotherapy, the aprepitant regimen (125/80/80 mg) combined with ondansetron and dexamethasone achieved an acute emesis control complete response rate of 83-89% and a delayed emesis control complete response rate of 68-75% 2
- For moderately emetogenic chemotherapy, the same aprepitant regimen showed an overall complete response of 51% vs. 43% with standard therapy (P = 0.015) 1, 2
Important Contraindications and Drug Interactions
- Absolute contraindications include administering aprepitant with pimozide, terfenadine, astemizole, or cisapride due to risk of serious or life-threatening reactions 1, 2, 3
- Aprepitant affects the metabolism of chemotherapy agents such as docetaxel, paclitaxel, etoposide, irinotecan, ifosfamide, imatinib, vinorelbine, vinblastine, and vincristine, as well as other medications like warfarin 1, 3