Persistent Tachycardia in a Patient on Clozapine

Abstract

<jats:p>Tachycardia emergent from clozapine treatment is usually transient, often missed, unreported, and therefore frequently goes untreated resulting in possible premature discontinuation of an otherwise effective treatment. Clozapine-induced tachycardia results from direct effects on the sympathetic nervous system including the blockade of cardiac muscarinic M<jats:sub>2</jats:sub> receptors, presynaptic <jats:italic>α</jats:italic><jats:sub>2</jats:sub> adrenoceptors, and indirect activation of the <jats:italic>β</jats:italic> adrenoceptors. Unfortunately, there are no clear guidelines for monitoring or treating tachycardia induced by clozapine. We present a case of a 55-year-old man with treatment-resistant schizophrenia initiated on clozapine who developed persistent tachycardia and right bundle branch block in the course of treatment. Tachycardia persisted despite treatment with metoprolol and necessitated a transfer to the intensive care unit. A reduction in clozapine dose with the addition of adjunctive antipsychotic(lurasidone) stabilized the patient’s heart rate. This case highlights the need for consistent physical examination and a multidisciplinary-based treatment approach for patients on clozapine. The case also suggests that clozapine dose reduction and combination antipsychotic treatments may preclude the need to discontinue clozapine in patients with persistent tachycardia.</jats:p>

Rethinking Clozapine: Lights and Shadows of a Revolutionary Drug

“…The most common cardiovascular adverse effect is sinus tachycardia, which results from direct effects on the sympathetic nervous system, including blockade of cardiac muscarinic M2 receptors and presynaptic adrenoceptors α2 and indirect activation of adrenoceptors β [178]. Sinus tachycardia is a rather common form of arrhythmia, with an incidence of 23.2%, whose manifestation is positively related with the dose of the compound and usually resolves in 4-6 weeks [178]. Normally, sinus tachycardia may not require any discontinuation of the therapy; however, in case of persistence, a cardio selective beta blocker (such as bisoprolol or ivabradine) may be administered.…”

“…Another frequent gastroenteric side effect is sialorrhea-maybe due to stimulation of muscarinic receptors, blockade of alpha-2 adrenergic receptors, or inhibition of the swallowing reflex-that often fades with the progressive tolerance to therapy. Otherwise, the use of sublingual anticholinergic drugs may be taken into consideration [176][177][178][179]. Lastly, dyspepsia and gastroesophageal reflux involve approximately 20% of patients during the first 6 weeks of Clozapine therapy.…”

When, Why and How to Re-challenge Clozapine following Myocarditis

“…This can be accompanied by a drop of systolic blood pressure. Importantly, isolated tachycardia and orthostatic dysregulation are common side-effects of clozapine [81,82,84,85]. The prevalence of tachycardia in patients with clozapine but without further signs for CIM ranges between 3 % and 67 % [84,85].…”

“…Importantly, isolated tachycardia and orthostatic dysregulation are common side-effects of clozapine [81,82,84,85]. The prevalence of tachycardia in patients with clozapine but without further signs for CIM ranges between 3 % and 67 % [84,85]. Therefore, both tachycardia and hypotension are of low diagnostic value, requiring additional parameters supporting CIM diagnosis to avoid premature clozapine termination [82].…”