Prescription medication · NK1 Receptor Antagonist (Antiemetic)
aprepitant
Also sold as Emend. Aprepitant is used to prevent nausea and vomiting caused by chemotherapy.
Data updated 2026-05-15
- 17,740
- FDA reportsModerately reported
- 22
- InteractionsSeveral interactions
- 44% less
- Generic vs brandReal savings
- 1
- Recall record
What the data shows
aprepitant (Emend) is a prescription NK1 Receptor Antagonist (Antiemetic), reported at a middle-of-the-pack volume (17,740 FDA reports), with a lower-cost generic available (44% less than brand).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
aprepitant (Emend) is a prescription NK1 Receptor Antagonist (Antiemetic). Aprepitant is used to prevent nausea and vomiting caused by chemotherapy.
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting. It belongs to a class of drugs called NK1 receptor antagonists.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$325.22/unit
Generic Price
$182.16/unit
Generic Savings
44%
Generic Available
Yes (3 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Aprepitant is used to prevent nausea and vomiting caused by chemotherapy.
Common side effects
Tiredness, Diarrhea, Weakness
Key warnings
Aprepitant can interact with other medicines.
The sections below are summarized in plain English from aprepitant's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Aprepitant blocks a substance in your body called substance P. Substance P can trigger nausea and vomiting. By blocking it, aprepitant helps reduce these side effects.
How to Take It
For chemotherapy, you will take aprepitant capsules 1 hour before your treatment on days 1, 2, and 3. The dose on day 1 is 125 mg, and on days 2 and 3 it is 80 mg. If you don't have chemotherapy on days 2 and 3, take aprepitant in the morning. For post-surgery nausea, adults take a 40 mg dose within 3 hours before anesthesia.
This is a plain-language summary of aprepitant's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
There is not enough information about the safety of aprepitant during pregnancy. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if aprepitant passes into breast milk, so discuss breastfeeding with your doctor.
This is a plain-language summary of aprepitant's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of aprepitant's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store aprepitant capsules at room temperature, between 68°F and 77°F.
Side Effects (from patient reports)
Based on 17,740 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for aprepitant, by number of reports
- Feeling sick to your stomach
Feeling sick to your stomach
2,147 reports
- Tiredness
Tiredness
1,769 reports
- Fever
Fever
1,589 reports
- Diarrhea
Diarrhea
1,543 reports
- Difficulty breathing
Difficulty breathing
1,508 reports
- Throwing up
Throwing up
1,474 reports
- Hair loss
Hair loss
1,274 reports
- Skin rash
Skin rash
1,210 reports
- Allergic reaction
Allergic reaction
1,133 reports
- Fever with low white blood cell count
Fever with low white blood cell count
1,043 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for aprepitant each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where aprepitant sits
aprepitant has more FDA adverse-event reports than 52% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is aprepitant; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 17,740 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
17,740
Reports Mentioning Death
2,942
16.6% of reports — not proof of cause
Hospitalization Reports
9,758
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | NAUSEA | 2,145 |
| 2 | FATIGUE | 1,769 |
| 3 | PYREXIA | 1,589 |
| 4 | DIARRHOEA | 1,542 |
| 5 | DYSPNOEA | 1,508 |
| 6 | VOMITING | 1,474 |
| 8 | ALOPECIA | 1,274 |
| 9 | RASH | 1,210 |
| 10 | HYPERSENSITIVITY | 1,133 |
| 11 | FEBRILE NEUTROPENIA | 1,043 |
| 12 | DECREASED APPETITE | 1,038 |
| 13 | PRURITUS | 1,020 |
| 14 | STOMATITIS | 992 |
| 15 | INFUSION RELATED REACTION | 972 |
| 16 | PAIN | 955 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Aprepitant can interact with other medicines. It can affect how well warfarin (a blood thinner) and hormonal birth control work. If you take warfarin, your doctor will check your blood. If you use hormonal birth control, use a backup method while taking aprepitant and for 28 days after your last dose.
Known Drug Interactions
Table 10: Effects of Aprepitant on the Pharmacokinetics of Other Drugs CYP3A4 Substrates Pimozide Clinical Impact Increased pimozide exposure Intervention Aprepitant is contraindicated [see Contraindications ( 4 )] . Table 10: Effects of Aprepitant on the Pharmacokinetics of Other Drugs CYP3A4 Substrates Pimozide Clinical Impact Increased pimozide exposure Intervention Aprepitant is contraindicated [see Contraindications ( 4 )] .
Mechanism: Aprepitant stops the body from breaking down pimozide, which can cause pimozide to build up to dangerous levels in the blood.
What to do: Do not take these two medications together because the combination is unsafe.
Benzodiazepines Clinical Impact Increased exposure to midazolam or other benzodiazepines metabolized via CYP3A4 (alprazolam, triazolam) may increase the risk of adverse reactions [see Clinical Pharmacology ( 12.3 )]. Benzodiazepines Clinical Impact Increased exposure to midazolam or other benzodiazepines metabolized via CYP3A4 (alprazolam, triazolam) may increase the risk of adverse reactions [see Clinical Pharmacology ( 12.3 )].
Mechanism: Aprepitant slows down how fast your body processes alprazolam, which causes the drug to build up in your blood. This can make you feel much more sleepy or dizzy than usual.
What to do: Your doctor may need to lower your dose of alprazolam. Watch closely for increased side effects like extreme drowsiness.
Intervention Avoid concomitant use of aprepitant Examples Moderate inhibitor: diltiazem Strong inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir Strong CYP3A4 Inducers Clinical Impact Substantially decreased exposure of aprepitant in patients chronically taking a strong CYP3A4 inducer may decrease the efficacy of aprepitant [see Clinical Pharmacology ( 12.3 )] . Intervention Avoid concomitant use of aprepitant Examples Moderate inhibitor: diltiazem Strong inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin,...
Mechanism: Diltiazem slows down the body's ability to process aprepitant, which can increase the amount of aprepitant in your blood.
What to do: Avoid taking these two medications at the same time.
Single 40 mg dose of aprepitant No dosage adjustment of oral dexamethasone needed Methylprednisolone Clinical Impact Increased methylprednisolone exposure [see Clinical Pharmacology ( 12.3 )]. Intervention 3-day aprepitant regimen Reduce the dose of intravenous methylprednisolone by approximately 25% Reduce the dose of oral methylprednisolone by approximately 50% Single 40 mg dose of aprepitant No dosage adjustment of methylprednisolone needed Chemotherapeutic agents that are metabolized by CYP3A4 Clinical Impact Increased exposure of the chemotherapeutic agent may increase the risk of...
Mechanism: Aprepitant prevents the body from breaking down methylprednisolone, which leads to higher levels of the steroid in your system.
What to do: Your doctor should reduce your dose of methylprednisolone by 25% to 50% depending on how it is given.
Intervention Avoid concomitant use of aprepitant Examples Moderate inhibitor: diltiazem Strong inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir Strong CYP3A4 Inducers Clinical Impact Substantially decreased exposure of aprepitant in patients chronically taking a strong CYP3A4 inducer may decrease the efficacy of aprepitant [see Clinical Pharmacology ( 12.3 )] . Intervention Avoid concomitant use of aprepitant Examples Moderate inhibitor: diltiazem Strong inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin,...
Mechanism: Ketoconazole strongly blocks the enzymes that clear aprepitant from your body, causing drug levels to rise.
What to do: You should avoid using these two medications together.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I take aprepitant with food?
What should I do if I experience side effects?
Can I take aprepitant if I am allergic to any of its ingredients?
Can aprepitant be used to treat nausea that has already started?
How long can I take aprepitant?
What dose of aprepitant should I take for chemotherapy?
What dose of aprepitant should I take for post-operative nausea?
Can children take aprepitant?
What if I am taking other medications?
Are there any reasons I should not take aprepitant?
What are the common side effects of aprepitant?
Does aprepitant interact with other medications?
What drug class is aprepitant?
Is there a generic version of aprepitant?
Is aprepitant safe during pregnancy?
Has aprepitant been recalled?
Active Recalls
Presence of particulate matter: potential presence of metal particulates in the product.
Merck Sharp & Dohme LLC
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Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for aprepitant
The FDA label for aprepitant (sold under brand names such as Emend) classifies it as a prescription-only medication in the NK1 Receptor Antagonist (Antiemetic) class. Aprepitant is used to prevent nausea and vomiting caused by chemotherapy. Official labeling lists 17 commonly reported side effects, including Tiredness, Diarrhea, Weakness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 17,740 voluntary reports. The database also lists 22 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $182.16 versus $325.22 for the brand - a 44% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 1 recall record on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 16, 2025
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages