Reported Reactions

Reactions

MedDRA preferred term · inflammation of the heart muscle

Myocarditis: adverse event reports recording this term

11,163 reports to FDA record it, 2004–2026; 0.1% of the database.

11,163
reports recording the term
0.1% of all reports
1,248
reports, 12 months to June 2026
1,154 in the 12 months before
99.6%
marked serious by the reporter
57.4% across all reports
20.6%
record death among outcomes, as reported
9.1% across all reports

11,163 reports in FDA's adverse event database record the MedDRA term "Myocarditis" (in plain words, inflammation of the heart muscle): 0.1% of all reports received between January 2004 and June 2026. Coders pick the term that best matches the reporter's description.

1,248 reports recorded it in the 12 months to June 2026, close to the 1,154 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Of reports recording this term, 99.6% are marked serious, 20.6% include death among the outcomes and 59% include hospitalisation, as reported.

The drugs listed most often as suspect products in those reports are Clozapine, Clozaril and Keytruda. That order mostly follows how many reports each drug has overall; the table also gives the term's share within each drug's own reports. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

073145Jul 2021: 87Aug 2021: 82Sep 2021: 73Oct 2021: 79Nov 2021: 95Dec 2021: 992022Jan 2022: 81Feb 2022: 78Mar 2022: 110Apr 2022: 104May 2022: 65Jun 2022: 82Jul 2022: 70Aug 2022: 72Sep 2022: 65Oct 2022: 92Nov 2022: 79Dec 2022: 822023Jan 2023: 70Feb 2023: 80Mar 2023: 116Apr 2023: 92May 2023: 81Jun 2023: 68Jul 2023: 67Aug 2023: 128Sep 2023: 70Oct 2023: 83Nov 2023: 80Dec 2023: 622024Jan 2024: 85Feb 2024: 81Mar 2024: 64Apr 2024: 133May 2024: 118Jun 2024: 82Jul 2024: 75Aug 2024: 63Sep 2024: 82Oct 2024: 102Nov 2024: 94Dec 2024: 1062025Jan 2025: 99Feb 2025: 76Mar 2025: 116Apr 2025: 145May 2025: 96Jun 2025: 100Jul 2025: 113Aug 2025: 105Sep 2025: 143Oct 2025: 109Nov 2025: 89Dec 2025: 1042026Jan 2026: 109Feb 2026: 112Mar 2026: 101Apr 2026: 88May 2026: 74Jun 2026: 101

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

Drugs listed as suspect products in these reports

DrugClassReports with this termShare of the drug's own reports
ClozapineAtypical antipsychotic1,3771.9%
ClozarilAtypical antipsychotic8571.8%
KeytrudaProgrammed death Receptor-1 blocking antibody7641.2%
NivolumabProgrammed death Receptor-1 blocking antibody5591.2%
OlanzapineAtypical antipsychotic5011.1%
PembrolizumabProgrammed death Receptor-1 blocking antibody4791.5%
OpdivoProgrammed death Receptor-1 blocking antibody4551%
CarboplatinPlatinum-based drug3920.4%
IpilimumabCTLA-4-directed blocking antibody2931.5%
AtezolizumabProgrammed death Receptor-1 blocking antibody2781.4%
PaclitaxelMicrotubule inhibitor2490.4%
CyclophosphamideAlkylating drug2470.2%
PrednisoneCorticosteroid2230.1%
QuetiapineAtypical antipsychotic2220.4%
YervoyCTLA-4-directed blocking antibody2111%
RisperidoneAtypical antipsychotic1940.4%
BevacizumabVascular endothelial growth factor inhibitor1900.3%
AripiprazoleAtypical antipsychotic1820.6%
FluorouracilNucleoside metabolic inhibitor1710.3%
RituximabCD20-directed cytolytic antibody1610.1%
MesalamineAminosalicylate1571.8%
Mycophenolate mofetilAntimetabolite immunosuppressant1490.2%
AcetaminophenNonsteroidal anti-inflammatory drug1480.2%
Valproic acidAnti-epileptic agent1440.7%
DurvalumabProgrammed death Ligand-1 blocker1391.8%

Drugs with a page on this site, ordered by the number of their reports recording this term. The last column is the term's share within that drug's own reports, against 0.1% across the whole database. 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."

By pharmacologic class

ClassReports with this termShare of class reportsMedian drug in class
Atypical antipsychotic3,7520.5%0%
Programmed death Receptor-1 blocking antibody2,7111.2%1.3%
Corticosteroid6270.1%0%
CTLA-4-directed blocking antibody6001.3%1.9%
Platinum-based drug5510.2%0.1%
Kinase inhibitor5430.1%0%
Nonsteroidal anti-inflammatory drug3960.1%0%
Nucleoside metabolic inhibitor3950.1%0.1%
Anti-epileptic agent3910.1%0%
Benzodiazepine3760.2%0.1%

Classes ordered by count. Class shares follow the class's overall report volume as much as anything else.

Patients in these reports

Patient age

Under 20.3%37
2 to 111.2%132
12 to 172.6%293
18 to 4428.8%3,215
45 to 6421.7%2,426
65 to 7412.9%1,436
75 and over9.6%1,072
Age not given22.9%2,552

Patient sex

Female37.8%4,221
Male50.8%5,671
Not given11.4%1,271

Grey bar: all 20,646,523 reports in the database. 22.1% of these reports give the United States as the country.

Questions about "Myocarditis"

What does "Myocarditis" mean in an adverse event report?

In plain language: inflammation of the heart muscle. It is a MedDRA preferred term, the dictionary FDA uses to code what a reporter described. The report's own description is not published by openFDA and is not shown here.

How many reports record myocarditis?

11,163 reports through June 2026 (0.1% of all reports), 1,248 of them in the latest 12 months.

Which drugs appear most often in these reports?

Clozapine (1,377), Clozaril (857), Keytruda (764), Nivolumab (559) and Olanzapine (501). Drugs with many reports overall lead almost every term's list. 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."

Does a drug appearing here mean it was responsible for this reaction?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

I have this symptom. What should I do?

This site cannot assess anyone. A pharmacist or clinician can; for an emergency, call the local emergency number. Nothing on this page is medical advice.

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. Terms are pooled across spelling and capitalisation variants of one MedDRA preferred term. 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.