Why the study?
Donepezil carries a documented risk for acquired long-QT syndrome and torsades de pointes, but mechanistic differences explaining why only donepezil poses this risk compared to other acetylcholinesterase inhibitors are not well established.
What is the comparative risk of cardiac arrhythmias, specifically acquired long-QT syndrome and torsades de pointes, among different acetylcholinesterase inhibitors used for dementia?
What is the comparative risk of cardiac arrhythmias, specifically acquired long-QT syndrome and torsades de pointes, among different acetylcholinesterase inhibitors used for dementia?
Donepezil carries a specific risk for acquired long-QT syndrome and torsades de pointes compared to other acetylcholinesterase inhibitors, which should be considered when prescribing for dementia.
Warrants vigilance for QT effects with donepezil; leaves open comparative safety versus other AChEIs pending prospective data.
Donepezil, galantamine, and rivastigmine are the three acetylcholinesterase inhibitors (AChEIs), out of a total of only four medications prescribed in the treatment of Alzheimer's Disease (AD) and related dementias. These medications are known to be associated with bradycardia given their mechanism of action of increasing acetylcholine (ACh). However, in March 2015, donepezil was added to the CredibleMeds "known-risk" category, a list where medications have a documented risk for acquired long-QT syndrome (ALQTS) and torsades de pointes (TdP) - a malignant ventricular arrhythmia that is a different adverse event than bradycardia (and is not necessarily associated with ACh action). The purpose of this article is to review the three AChEIs, especially with regards to mechanistic differences that may explain why only donepezil poses this risk; several pharmacological mechanisms may explain why. However, from an empirical point-of-view, aside from some case-reports, only a limited number of studies have generated relevant information regarding AChEIs' and electrocardiogram findings; none have specifically compared donepezil against galantamine or rivastigmine for malignant arrhythmias such as TdP. Currently, the choice of one of the three AChEIs for treatment of AD symptoms is primarily dependent upon clinician and patient preference. However, clinicians should be aware of the potential increased risk associated with donepezil. There is a need to examine the comparative risk of malignant arrhythmias among AChEIs users in real-world practice; this may have important implications with regards to changes in AChEI prescribing patterns.
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Huang et al. (2020) studied this question.
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