Clozapine Re-challenge in a Patient With Pericarditis: A Case Report.

Pericarditis is a rare but potentially severe adverse event associated with clozapine treatment, which often results in clozapine discontinuation. There is limited evidence or guidance relating to the safety of reintroducing clozapine in patients who have developed pericarditis. In this report, we describe a successful clozapine re-challenge in a 53-year-old male patient with treatment-resistant schizophrenia who developed pericarditis after many years of stability on clozapine. He was admitted with a sudden onset of pleuritic and positional chest pain and was found to have widespread saddling ST elevation and elevated troponin and inflammatory markers. The echocardiogram demonstrated pericarditis and a small pericardial effusion. Treatment was initiated for pericarditis, and clozapine was suspended. Following symptom resolution, the patient was transferred to inpatient psychiatry, where clozapine reintroduction began on day 9 of admission. A standard clozapine titration schedule was followed over 15 days with weekly monitoring. Clozapine was successfully re-titrated without any clinical, biochemical, or radiological deterioration of pericarditis. This case highlights the safe and successful re-titration of clozapine in patients presenting with pericarditis, within weeks of initial presentation and with ongoing mild biochemical disturbances without any significant deterioration in cardiovascular status or function.