Incidence of Myocarditis Caused by Drugs Used for Ulcerative Colitis as Examined Using VigiBase, a Spontaneous Adverse Drug Reaction Reporting Database

Although myocarditis is listed as a serious adverse reaction in the package inserts of mesalazine and some other anti-ulcerative colitis (UC) drugs currently in use, and regulatory authorities have issued related warnings, the detailed characteristics of anti-UC drug-induced myocarditis remain unknown. We aimed to investigate the association between UC drugs and myocarditis development as an adverse event and its characteristics using data from a spontaneous adverse drug reaction reporting database. We searched for adverse event signals of five drugs, mesalazine, sulfasalazine, azathioprine, mercaptopurine, and budesonide, listed in the treatment guidelines for UC, using VigiBase. The information component was calculated, and a signal was considered present when the lower limit of the 95% confidence interval of the information component exceeded zero. The total number of VigiBase and myocarditis (as a target adverse event) reports was 38459016 and 71571, respectively. No trend was identified based on age or sex. Analysis of the five UC drugs for severity in VigiBase showed that most patients recovered, with a low reported mortality rate. However, the time to onset of adverse drug reactions varied among the drugs. Mesalazine signals were detected regardless of age or sex. This finding suggests that myocarditis, an adverse event, may be a potential complication regardless of patient characteristics. Our results also indicate that UC itself may induce myocarditis. Our findings warrant multifaceted investigations, including basic and clinical studies, on the characteristics of each drug regarding the development of myocarditis as an adverse event.