Clozapine-related tachycardia: A conundrum to identify and treat.

OBJECTIVE: This study examined the rates and persistence of clozapine-induced tachycardia and heart-rate differences in patients treated with ß-blockers in the largest sample of patients with a psychotic disorder to date. METHOD: An audit of medical files for 101 patients who attended a clozapine community clinic and analysis of monthly measurements of resting heart rates. RESULTS: 51% met the clinical criteria for tachycardia. Heart rates were stable over time. ß-blockers were associated with small but significant reductions in heart rates. CONCLUSION: The cardiovascular risks of clozapine are often overlooked. ß-blockers are useful in lowering heart rates but they may be insufficient to reduce cardiac risk.