Pharmacologic class (EPC) · 3 drug pages

Substance P/Neurokinin-1 receptor antagonist: adverse event reports filed with FDA

8,823 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

8,823
reports across the class: 0% of all reports; 635
reports, 12 months to June 2026: 1,056 in the 12 months before; 83.3%
marked serious by the reporter: 57.4% across all reports; 3
drugs with a page: brand and generic names counted separately

Substance P/Neurokinin-1 receptor antagonist is a pharmacologic class (an FDA Established Pharmacologic Class) with 3 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 8,823 adverse event reports received by FDA, 0% of the database, from January 2004 to June 2026.

635 reports arrived in the 12 months to June 2026, down 40% from 1,056 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 83.3% of the class's reports are marked serious, 21.9% record death among the outcomes and 51.9% record hospitalisation, as reported.

Across the class the reactions recorded most often are dyspnoea (17%), pyrexia (16%) and fatigue (15.9%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
EmendAprepitant	brand	5,750	161	77.5%	Dyspnoea
Aprepitant	generic	2,486	328	96.8%	Fatigue
Fosaprepitant	generic	587	146	82.6%	Dyspnoea

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Dyspnoeashortness of breath17%1,496
Pyrexiafever16%1,413
Fatiguetiredness15.9%1,404
Hypersensitivityan allergic-type reaction14.9%1,312
Rashskin rash13.8%1,217
Alopeciahair loss13%1,151
Pruritusitching12.8%1,133
Nauseafeeling sick12.6%1,115
Infusion related reactiona reaction during or soon after an infusion12.6%1,114
Gastrointestinal disorder12.6%1,110
Confusional stateconfusion12.5%1,106
Glossodynia12.4%1,097
Hand deformity12.4%1,094
Folliculitis12.3%1,084
Helicobacter infection12.3%1,083
Impaired healingslow healing12.2%1,075
Hepatic enzyme increasedraised liver enzymes12.1%1,068
Duodenal ulcer perforation12%1,062
Systemic lupus erythematosuslupus, an autoimmune disease11.8%1,040
Stomatitissore mouth11.7%1,032
Infectionan infection, type not specified11.5%1,019
Sinusitissinus infection11.5%1,013
Joint swellinga swollen joint11.4%1,005
Synovitis11.3%997
Weight increasedweight gain11.3%996

Solid bar: share of all class reports. Hollow bar: the median share across the 3 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death21.9%1,933

Life-threatening21.7%1,919

Hospitalisation (initial or prolonged)51.9%4,577

Disability21.2%1,870

Congenital anomaly4.8%421

Other serious56.3%4,969

Not serious16.7%1,476

Patient age

Under 20.3%25

2 to 110.6%54

12 to 171.6%143

18 to 4422.3%1,964

45 to 6429.6%2,616

65 to 7414.9%1,311

75 and over5%437

Age not given25.8%2,273

Who reported

Physician29.8%2,629

Pharmacist14.1%1,242

Other health professional39.6%3,491

Lawyer0.1%5

Consumer or non-health professional15.4%1,356

Not given1.1%100

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Substance P/Neurokinin-1 receptor antagonist reports

Which drugs are in the Substance P/Neurokinin-1 receptor antagonist class on this site?

Emend, Aprepitant and Fosaprepitant. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

8,823 reports through June 2026, 635 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

dyspnoea (17%), pyrexia (16%), fatigue (15.9%), hypersensitivity (14.9%) and rash (13.8%).

Can the members table be used to rank the drugs?

No. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.