Reported Reactions

Adverse event reports that FDA received

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Mass adverse event reports that record this term

Kind of term
MedDRA preferred term

What a report is

A report is not proof that the drug was the cause of the event.

FDA says:

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.

Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on . The data have the reports that FDA received through .

FDA also says:

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 has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

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.

Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on .

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

Reports on file

From January 2004 to June 2026, FDA received 13,809 adverse event reports that record the MedDRA preferred term Mass. The person who codes a report selects the term that agrees best with the description of the reporter.

FDA received 591 reports in the 12 months to June 2026 and 672 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

By reports in the 12 months to June 2026, this term was number 893 of 1,436 reaction terms with a page. Of the 1,332,454 drug reports that FDA received in the 12 months to June 2026, 591 (under 0.1%) record this term. Reports for female patients were 60.5% of the reports that record this term and 52.7% of all drug reports.

The number of people who use the product is not in the data. A count is not a rate.

MedDRA

The Medical Dictionary for Regulatory Activities. The person who codes a report selects the preferred term that agrees best with the description of the reporter. FDA does not publish the description.

Data version

openFDA FAERS release of 29 Oct 2026. Reports received through 30 Jun 2026.

Drugs in these reports

The table has the 79 drug pages with 50 or more reports that record this term. The rows are in order of name. A drug page with fewer reports for this term is not in the table. The counts are the counts that the site keeps for each reaction term, and a count can be lower than the count of FDA.

FDA says:

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.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.

Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .

Drugs that the reports with the term Mass name as a suspect product, in order of name
DrugClassReports with this term
AbataceptSelective T cell costimulation modulator56
ActemraInterleukin-6 receptor antagonist305
AdalimumabTumor necrosis factor blocker64
AfinitorKinase inhibitor72
AravaAntirheumatic agent74
Aredia94
AvonexInterferon beta112
BOTOX CosmeticAcetylcholine release inhibitor57
Bydureon127
Bydureon Bcise61
CapecitabineNucleoside metabolic inhibitor70
CarboplatinPlatinum-based drug53
Certolizumab pegolTumor necrosis factor blocker55
CimziaTumor necrosis factor blocker107
CisplatinPlatinum-based drug50
Copaxone67
CosentyxInterleukin-17A antagonist231
CyclophosphamideAlkylating drug174
CyclosporineCalcineurin inhibitor immunosuppressant58
DexamethasoneCorticosteroid79
DoxorubicinAnthracycline topoisomerase inhibitor102
Doxorubicin hydrochlorideAnthracycline topoisomerase inhibitor71
DupixentInterleukin-4 receptor alpha antagonist78
EnbrelTumor necrosis factor blocker776
EovistGadolinium-based contrast agent73
EtoposideTopoisomerase inhibitor63
ForteoParathyroid hormone analog247
FosamaxBisphosphonate128
FurosemideLoop diuretic50
Gadolinium76
Gadolinium in Drug73
GilenyaSphingosine 1-phosphate receptor modulator50
HerceptinHER2/neu receptor antagonist60
Human immunoglobulin gHuman immunoglobulin G60
Humira1,247
HydroxychloroquineAntimalarial70
IbranceKinase inhibitor66
ImbruvicaKinase inhibitor165
InfliximabTumor necrosis factor blocker71
JakafiJanus kinase inhibitor94
KisqaliKinase inhibitor74
Magnevist154
MethotrexateFolate analog metabolic inhibitor278
Methotrexate sodiumFolate analog metabolic inhibitor63
MultiHanceGadolinium-based contrast agent154
Mycophenolate mofetilAntimetabolite immunosuppressant96
OcrevusCD20-directed cytolytic antibody81
OmniscanParamagnetic contrast agent147
Optimark149
OrenciaSelective T cell costimulation modulator112
PegasysInterferon alpha91
PomalystThalidomide analog54
PrednisoloneCorticosteroid105
PrednisoneCorticosteroid297
ProliaRANK ligand inhibitor106
RamiprilAngiotensin converting enzyme inhibitor61
RemicadeTumor necrosis factor blocker294
RepathaPCSK9 inhibitor64
RevlimidThalidomide analog253
RibavirinNucleoside analog antiviral71
RinvoqJanus kinase inhibitor118
RituxanCD20-directed cytolytic antibody93
RituximabCD20-directed cytolytic antibody266
SandostatinSomatostatin analog157
Sandostatin LAR Depot204
SimponiTumor necrosis factor blocker63
SkyriziInterleukin-23 antagonist87
StelaraInterleukin-12 antagonist62
TacrolimusCalcineurin inhibitor immunosuppressant109
TrulicityGLP-1 receptor agonist71
TysabriIntegrin receptor antagonist99
Vincristine81
Vivitrol59
XeljanzJanus kinase inhibitor168
XelodaNucleoside metabolic inhibitor50
XeominAcetylcholine release inhibitor50
XolairAnti-IgE132
ZelborafKinase inhibitor228
Zometa184

The page of each drug has the count of each reaction term in its reaction lookup.

Drug classes in these reports

The table has the 35 pharmacologic classes with 100 or more reports that record this term. The rows are in order of name.

FDA says:

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.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.

Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .

Pharmacologic classes of the drugs that the reports with the term Mass name, in order of name
ClassReports with this term
Acetylcholine release inhibitor163
Alkylating drug223
Anthracycline topoisomerase inhibitor183
Anti-IgE167
Antimalarial162
Antimetabolite immunosuppressant116
Atypical antipsychotic115
Bisphosphonate216
Calcineurin inhibitor immunosuppressant181
CD20-directed cytolytic antibody477
Corticosteroid568
Factor Xa inhibitor100
Folate analog metabolic inhibitor344
Gadolinium-based contrast agent154
GLP-1 receptor agonist193
HER2/neu receptor antagonist103
Human immunoglobulin G111
Integrin receptor antagonist143
Interferon beta158
Interleukin-17A antagonist271
Interleukin-6 receptor antagonist326
Janus kinase inhibitor431
Kinase inhibitor1,081
Nucleoside metabolic inhibitor222
Opioid agonist125
Paramagnetic contrast agent147
Parathyroid hormone analog259
Platinum-based drug128
Poly(ADP-Ribose) polymerase inhibitor100
Proton pump inhibitor103
RANK ligand inhibitor119
Selective T cell costimulation modulator168
Somatostatin analog206
Thalidomide analog329
Tumor necrosis factor blocker1,526

A class with many reports in all has many reports for almost every term.

Reports by month

Reports that record Mass, by month, five years to June 2026
05010020222023202420252026

FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Patients in these reports

Age of the patient in the reports that record Mass
AgeReportsShareShare as a bar
Under 2430.3%
2 to 111180.9%
12 to 171571.1%
18 to 441,50210.9%
45 to 643,64726.4%
65 to 741,77012.8%
75 and over1,1148.1%
Age not given5,45839.5%
Sex of the patient in the reports that record Mass
SexReportsShareShare as a bar
Female8,35860.5%
Male4,31431.2%
Unknown or not given1,1378.2%

Age and sex are as the report gives them. 66% of these reports give the United States as the country.

Terms near this one

Official pages

The site checked these addresses on . The links open in a new tab.

Cite this page

Reported Reactions. Mass: adverse event reports that record this term. https://reportedreactions.com/reaction/mass/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of . Reports received through .

Where the data come from

The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 29 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Nov 2026. A class is the pharmacologic class (EPC) of the FDA label.

The count has the reports with each spelling of one MedDRA preferred term. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.

Questions

What does Mass mean in an adverse event report?

It is a MedDRA preferred term. FDA codes the description of a reporter with the MedDRA dictionary. The openFDA files do not have the description itself, and this site does not show it.

Does a drug in the table mean that the drug was responsible for this reaction?

No. FDA says:

No individual drug is connected to any individual reaction.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

What does this page tell a person who has this symptom?

This page gives counts of reports. It cannot assess a person. A pharmacist or a clinician can assess a person.

If this is a medical emergency, please call 911.

Source: FDA, MedWatch Online Voluntary Reporting Form. The site read the page on .