What the label lists and what reports show
Fosaprepitant side effects
Fosaprepitant's FDA label: “Most common adverse reactions in adults (≥2%) are: fatigue, diarrhea, neutropenia, asthenia, anemia, peripheral neuropathy, leukopenia, dyspepsia, urinary tract infection, pain in extremity.” FAERS holds 13,668 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is dyspnoea (1,268 reports).
- Generic listed
- A presentation discontinued
Check it at the source: the fosaprepitant FDA label on DailyMed (effective July 29, 2026, AVYXA Pharma, LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of NAVITRUX?NAVITRUX may cause serious side effects, including: ● Serious allergic reactions. Allergic reactions can happen with fosaprepitant given by intravenous (IV) infusion and may be serious. Tell your healthcare provider right away if you have hives, rash, itching, flushing or redness of your face or skin, trouble breathing or swallowing, dizziness, a rapid or weak heartbeat, or you feel faint during or soon after you receive NAVITRUX, as you may need emergency medical care. Severe skin reactions, which may include rash, skin peeling, or sores, may occur. ● Infusion site reactions (ISR) at or near the infusion site have happened with fosaprepitant given by intravenous (IV) infusion. Most severe ISR have happened with a certain type of chemotherapy medicine that can burn or blister your skin (vesicant) with side effects, including pain, swelling and redness. […]
Source: FDA drug label, AVYXA Pharma, LLC, effective July 29, 2026 (SPL set a41b7c3a-1376-43a7-b5b9-6ba2eba1e169), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions in adults (≥2%) are: fatigue, diarrhea, neutropenia, asthenia, anemia, peripheral neuropathy, leukopenia, dyspepsia, urinary tract infection, pain in extremity.
Table 6: Most Common Adverse Reactions in Patients Receiving MEC a
| Reaction | Intravenous fosaprepitant, ondansetron, and dexamethasone b (N=504) | Ondansetron and dexamethasone c (N=497) |
|---|---|---|
| fatigue | 15% | 13% |
| diarrhea | 13% | 11% |
| neutropenia | 8% | 7% |
| asthenia | 4% | 3% |
| anemia | 3% | 2% |
| peripheral neuropathy | 3% | 2% |
| leukopenia | 2% | 1% |
| dyspepsia | 2% | 1% |
| urinary tract infection | 2% | 1% |
| pain in extremity | 2% | 1% |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in the labeling: Hypersensitivity Reactions [see Warnings and Precautions (5.2) ] Infusion Site Reactions [see Warnings and Precautions (5.3) ] Most common adverse reactions in adults (≥2%) are: fatigue, diarrhea, neutropenia, asthenia, anemia, peripheral neuropathy, leukopenia, dyspepsia, urinary tract infection, pain in extremity. ( 6.1 ) Adverse reactions in pediatrics are similar to adults. To report SUSPECTED ADVERSE REACTIONS, contact Avyxa Pharma, LLC at 1-888-520-0954 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety of NAVITRUX has been established from adequate and well-controlled studies of another intravenous formulation of fosaprepitant [see Clinical Studies (14) ]. Below is a display of the adverse reactions of fosaprepitant in these studies. The overall safety of fosaprepitant was evaluated in approximately 1800 adult and pediatric patients.
Source: FDA drug label, AVYXA Pharma, LLC, effective July 29, 2026 (SPL set a41b7c3a-1376-43a7-b5b9-6ba2eba1e169), via openFDA; the full label on DailyMed
What do FAERS reports show?
13,668 reports list fosaprepitant among the medicines taken, each a report of something that happened, not proof the medicine caused it; 2,220 are coded as a death and 7,095 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 9 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Fosaprepitant: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions