Myocarditis related to clozapine treatment

Myocarditis has in several case reports been associated with use of clozapi ne. Eight cases of myocarditis during treatment with clozapine that were su bmitted to the Swedish Adverse Drug Reaction Advisory Committee and 18 case s that were reported in the literature are summarized. As part of the routi ne signal detection process on the World Health Organization (WHO) Program on International Drug Monitoring database, which contains more than two mil lion case reports of spontaneously reported suspected adverse drug reaction s, a Bayesian confidence propagation neural network (BCPNN) is used. This a rticle also shows the retrospective output of the BCPNN over time for cloza pine and myocarditis and discusses its implications. Ln 19 (79%; duration o f treatment not stated for 2 patients) of 24 patients with myocarditis, the symptoms occurred within the first 6 weeks of clozapine treatment. Many pa tients shared a similar clinical course, with symptoms such as an influenza -like illness, fever, sinus tachycardia, hypotension, chest discomfort, and heart failure. The reaction was fatal in 12 (46%) of these patients. The o ther patients generally had a prompt recovery. By using the BCPNN technique , a quantitative association between clozapine and myocarditis was demonstr ated, and the association might have been highlighted for clinical review i n 1994 had this BCPNN method been in use at the WHO center at the time. Myo carditis seems to be a rare and potentially lethal adverse effect of clozap ine. Admittance for observation, interruption of the clozapine treatment, a nd treatment with corticosteroids should be considered for patients in whom this reaction is suspected.