ABSTRACT
PURPOSE: Clozapine-associated myocarditis (CAM) is a serious complication, mostly occurring in the first month of treatment. Public mental health in South Australia introduced a screening protocol in 2011 using baseline and weekly C-reactive protein and troponin. The aim of this study was to assess protocol adherence and management of cases with positive screening results. METHODS: We identified all patients commenced on clozapine in our area between 2012 and 2015. Those with abnormal C-reactive protein and/or troponin in the first 4 weeks of treatment were identified (potential cases). For those, we collected clinical characteristics and test results and reviewed their management. FINDINGS: Protocol compliance increased to 80%. We identified 24 potential CAM cases, 8 at high risk based on established definition (7.6% of new commencements) and 9 formally diagnosed from 143 commenced on clozapine. Potential cases not meeting CAM definition were significantly more likely commenced on clozapine for the first time and have preexisting respiratory disease. Likely CAM cases were younger, and more often prescribed additional antipsychotics, specifically quetiapine. Seven (78%) of 9 patients diagnosed with CAM met published CAM definition. In 14 undiagnosed potential cases, 10 (71%) did not have timely testing to exclude CAM. CONCLUSIONS: Maintaining a high index of suspicion, clinical monitoring and timely testing is important to supplement CAM screening protocols. More research is needed to identify those that can be safely rechallenged or even continue clozapine treatment with monitoring.