Disproportionality analysis of the FDA Adverse Event Reporting System (2004–2023) identified 9014 cases of drug-induced myocarditis, with chemotherapeutic agents most commonly associated and phendimetrazine showing the strongest disproportionality signal.
Drug-induced myocarditis represented a rare but increasing proportion of adverse event reports in the FDA Adverse Event Reporting System from 2004 to 2023.
Drug-induced myocarditis cases were most common in male patients and in those aged 41–64 years.
Chemotherapeutic agents were the drug group most commonly associated with myocarditis, making cancer the leading indication.
Clozapine was the most frequently reported individual drug associated with myocarditis, while phendimetrazine showed the strongest disproportionality signal.
The United States reported the highest number of drug-induced myocarditis cases, with physicians and pharmacists submitting the majority of reports.
Clinical outcomes of drug-induced myocarditis were serious, with substantial rates of hospitalization and death.
This research examined nearly 20 years of FDA safety reports (2004–2023) to better understand which drugs are most commonly linked to myocarditis — an inflammation of the heart muscle that can be life-threatening. Out of more than 20 million adverse event reports, the researchers identified 9,014 cases of drug-induced myocarditis, representing a small but growing share of safety reports. The number of annual cases rose dramatically over the study period, from 101 in 2004 to 1,543 in 2023. The findings suggest that cancer drugs (chemotherapeutics) are the group most commonly associated with myocarditis, with cancer being the leading reason patients were taking the implicated medications. Among individual drugs, clozapine — an antipsychotic medication — was most frequently reported, while a weight-loss drug called phendimetrazine showed the strongest statistical link to myocarditis. Cases were more common in men and in middle-aged adults (41–64 years). Importantly, outcomes were serious: over a third of patients required hospitalization, and nearly 13% died. This research suggests that healthcare providers and regulatory agencies should maintain heightened vigilance for signs of myocarditis in patients taking high-risk drugs, particularly chemotherapy agents and clozapine. The rising trend in reports over time — likely reflecting both increased drug use and improved reporting — highlights the growing importance of pharmacovigilance programs designed to detect and respond to rare but dangerous drug side effects.
Pang J, Zhu W, Zhang Y, Guo W. (2026). Disproportionality analysis of drug-induced myocarditis: Insights from the Food and Drug Administration Adverse Event Reporting System database.. The Journal of international medical research. https://doi.org/10.1177/03000605261475733