Objectives: Clozapine is the most efficacious treatment for treatment-resistant schizophrenia; however its use can be limited by intolerability. Sinus tachycardia is a common adverse event associated with clozapine use, which may lead to the premature discontinuation of clozapine. Traditionally, β blockers are used to treat clozapine-associated tachycardia, though problems with intolerability and ineffectiveness can limit their utility.

Methods: In this article, we present two cases of patients with treatment-resistant schizophrenia who developed symptomatic tachycardia associated with clozapine therapy.

Results: We demonstrate that the novel heart rate controlling agent ivabradine can be effectively and safely used to control the heart rate and to allow for continued treatment with clozapine.

Conclusion: This is the first report in the literature demonstrating that ivabradine appears to be a well tolerated agent, which should be considered as a symptomatic treatment of clozapine-induced tachycardia if the use of a β blocker fails due to a lack of response or intolerability.