Aprepitant: Complete Guide To Prevent Chemotherapy Sickness
Comprehensive guide to Aprepitant (Emend): usage, dosage, side effects, and key information for preventing nausea from chemotherapy.
Aprepitant, sold under the brand name Emend, is a medication specifically designed to prevent nausea and vomiting associated with cancer chemotherapy and postoperative recovery. As a substance P/neurokinin 1 (NK1) receptor antagonist, it targets the brain’s vomiting center to block signals that trigger sickness, making it highly effective when combined with other antiemetics like dexamethasone and 5-HT3 antagonists.
About aprepitant
Aprepitant works by selectively blocking NK1 receptors in the central nervous system, which play a key role in the emetic response. This mechanism complements other anti-nausea drugs, providing superior control over both acute (within 24 hours) and delayed (24-120 hours) phases of chemotherapy-induced nausea and vomiting (CINV). It is available as capsules (40 mg, 80 mg, 125 mg) and oral suspension, with formulations approved for adults and pediatric patients.
Clinical studies demonstrate that aprepitant regimens significantly improve complete response rates (no vomiting and no rescue therapy needed). For highly emetogenic chemotherapy like cisplatin, aprepitant triples the likelihood of preventing delayed CINV compared to standard therapy alone.
Before taking aprepitant
Allergy and Medical History
Do not take aprepitant if you are allergic to it or any ingredients in Emend. Inform your doctor about liver problems, as dosage adjustments may be needed for moderate impairment (no adjustment for mild or end-stage renal disease).
Pregnancy and Breastfeeding
- Pregnancy: Aprepitant is not recommended during pregnancy unless benefits outweigh risks. Animal studies show no direct harm, but human data is limited. Use effective contraception during treatment and for 1 month after, as it may reduce hormonal contraceptive efficacy.
- Breastfeeding: It is unknown if aprepitant passes into breast milk; avoid breastfeeding during treatment and for 5 days after the last dose.
Other Medicines
Aprepitant interacts with CYP3A4-metabolized drugs (e.g., pimozide, pimozide—contraindicated; warfarin, oral contraceptives—monitor closely). It can increase levels of benzodiazepines, steroids, and decrease levels of tolbutamide. Always provide a full medication list to your healthcare provider.
| Drug Class | Effect | Recommendation |
|---|---|---|
| Pimozide | Increased risk of serious cardiac events | Contraindicated |
| Warfarin | Decreased INR | Monitor INR closely |
| Oral Contraceptives | Reduced efficacy | Use non-hormonal backup |
| Benzodiazepines (e.g., midazolam) | Increased exposure | Reduce dose; monitor |
How and when to take aprepitant
Standard Adult Dosage for CINV
Aprepitant is given as a 3-day regimen with a 5-HT3 antagonist (e.g., ondansetron) and dexamethasone:
- Day 1: 125 mg capsule 1 hour before chemotherapy.
- Day 2: 80 mg capsule 1 hour after chemotherapy.
- Day 3: 80 mg capsule 1 hour after chemotherapy.
Take capsules whole with water, with or without food. For oral suspension, healthcare providers prepare it per specific instructions (e.g., mix pouch contents with 4.6 mL water, swirl 20 times, invert 5 times; stable for 72 hours refrigerated).
Pediatric Dosage (6 months-17 years)
Weight-based dosing for 3 days:
| Weight | Day 1 | Day 2-3 |
|---|---|---|
| ≥40 kg | 125 mg | 80 mg |
| 30-<40 kg | 4.2 mL | 2.7 mL |
| 20-<30 kg | 3.0 mL | 1.9 mL |
| 15-<20 kg | 2.3 mL | 1.5 mL |
| 10-<15 kg | 1.9 mL | 1.2 mL |
| 6-<10 kg | 1.5 mL | 1.0 mL |
For postoperative nausea and vomiting (PONV), a single 40 mg dose is given 3 hours before anesthesia.
Preparation of Oral Suspension
- Fill mixing cup with room temperature water.
- Add 4.6 mL using 5 mL dispenser.
- Shake and open pouch; pour into water.
- Swirl 20 times, invert 5 times; check for clumps/foam.
- Fill appropriate dispenser (1 mL or 5 mL); refrigerate up to 72 hours.
Missed Dose
If you miss a dose, take it as soon as remembered unless close to the next dose. Do not double up. Continue the regimen as prescribed.
Dosage for adults and children
Adults: 125/80/80 mg over 3 days for CINV; 40 mg single dose for PONV.
Children: Weight-tiered oral suspension as above; for adolescents, same as adults.
No adjustment for renal impairment; caution in moderate hepatic impairment.
Side-effects of aprepitant
Common side effects (≥5%): fatigue, diarrhea, constipation, anorexia, neutropenia, asthenia, hiccups. Serious risks include hypersensitivity reactions and drug interactions leading to QT prolongation.
- Frequent: Tiredness (up to 17%), nausea (13%), hiccups (12%), constipation (10%).
- Serious (rare): Anaphylaxis, severe hepatic injury. Seek immediate help for rash, itching, swelling, or breathing difficulty.
Pediatric side effects mirror adults, with additional risks of febrile neutropenia.
How to cope with side effects of aprepitant
- Fatigue: Rest, maintain light activity; report if persistent.
- Diarrhea/Constipation: Stay hydrated; use over-the-counter remedies as advised.
- Hiccups: Breathe into a paper bag or sip cold water slowly.
- Anorexia: Eat small, frequent nutrient-dense meals.
Most effects are mild and resolve post-treatment. Contact your doctor if severe or lasting.
Pregnancy and breastfeeding with aprepitant
Aprepitant crosses the placenta; category B in some classifications but use cautiously. It induces CYP3A4, affecting contraceptives—use barrier methods. Discontinue breastfeeding for 5 days post-dose.
Other precautions for aprepitant
- Monitor liver function in hepatic impairment.
- Avoid alcohol, as it may worsen side effects.
- Store capsules at room temperature; suspension refrigerated post-preparation.
Common questions about aprepitant
Is aprepitant a steroid?
No, it is an NK1 receptor antagonist, not a steroid. It is often used with dexamethasone (a steroid).
Does aprepitant cause drowsiness?
It may cause fatigue, but less than some other antiemetics. Avoid driving if affected.
How long does aprepitant take to work?
Effects begin within hours, providing coverage for 24-120 hours post-chemotherapy.
Can I take aprepitant with food?
Yes, food does not affect absorption.
Is aprepitant safe for long-term use?
Typically used in short 3-day courses per chemotherapy cycle; multiple cycles studied up to 6.
Alternatives to aprepitant
| Drug | Mechanism | Use |
|---|---|---|
| Ondansetron | 5-HT3 antagonist | Acute CINV |
| Dexamethasone | Corticosteroid | Adjunct |
| Fosaprepitant (IV) | Prodrug of aprepitant | When oral not feasible |
| Netupitant/Palonosetron (Akynzeo) | NK1 + 5-HT3 | Alternative combo |
Frequently Asked Questions (FAQs)
Q: Who should take aprepitant?
A: Patients receiving highly/moderately emetogenic chemotherapy or at risk of PONV.
Q: Can children under 6 months use it?
A: Safety not established; approved from 6 months based on weight.
Q: What if I overdose?
A: Symptoms include asthenia, diarrhea; seek emergency care. No specific antidote.
Q: Does it prevent all nausea?
A: Highly effective in regimens (70-80% complete response), but not 100%; combine therapies.
References
- EMEND (aprepitant) Capsules – DailyMed — National Library of Medicine, NIH. 2024-07-05. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=696f9e80-9cae-403b-de9e-078343ce4713
- EMEND (aprepitant) EPAR Product Information — European Medicines Agency. (Recent update). https://www.ema.europa.eu/en/documents/product-information/emend-epar-product-information_en.pdf
- Aprepitant: Uses, Interactions, Mechanism of Action — DrugBank Online. (Accessed 2026). https://go.drugbank.com/drugs/DB00673
- Aprepitant – StatPearls — NCBI Bookshelf, NIH. 2023. https://www.ncbi.nlm.nih.gov/books/NBK551588/
- Fosaprepitant IV (Emend®) – OncoLink — Abramson Cancer Center, UPenn. (Recent). https://www.oncolink.org/cancer-treatment/oncolink-rx/aprepitant-oral-emend-R-fosaprepitant-iv-emend-R-aprepitant-iv-cinvanti-R
Similar Articles
Read full bio of medha deb
