RT Journal Article SR Electronic T1 Plasma N-terminal pro-B-type natriuretic peptide (BNP) in mesalazine-induced myopericarditis JF BMJ Case Reports JO BMJ Case Reports FD BMJ Publishing Group Ltd SP e229142 DO 10.1136/bcr-2018-229142 VO 12 IS 4 A1 Theodoros Paschalis A1 Myrella Paschali A1 Amit K J Mandal A1 Constantinos G Missouris YR 2019 UL http://casereports.bmj.com/content/12/4/e229142.abstract AB Mesalazine (5-aminosalicylic acid)-based products are a widely used treatment for inflammatory bowel disease in children and adults. Associated myopericarditis is an uncommon but recorded phenomenon related to drug hypersensitivity. Unless recognised, this important complication may culminate in the development of dilated cardiomyopathy and severe heart failure. We report the case of a boy with Crohn’s disease who developed myopericarditis 14 days after starting treatment with mesalazine. Discontinuation of the drug rapidly led to normalisation of left ventricular structure and function, and a parallel improvement in the levels of plasma N-terminal pro-B-type natriuretic peptide and other markers of myocardial damage. Clinicians should be aware of this potentially life-threatening adverse effect of mesalazine therapy, which is quickly and fully reversible on cessation of the agent.