Syncope secondary to second-degree atrioventricular block with donepezil use

Area of Science:

• Neurology
• Cardiology
• Pharmacology

Background:

• Donepezil is a common acetylcholinesterase inhibitor for Alzheimer's disease dementia.
• Gastrointestinal side effects are well-known, but cardiovascular effects are less common.
• Previous reports linked donepezil's cardiac events to pre-existing conduction defects.

Observation:

• A woman with early-onset Alzheimer's disease and no cardiac history was treated with donepezil.
• She developed second-degree atrioventricular (AV) block within weeks of initiating therapy.
• No other cardiac risk factors or concurrent medications were identified.

Findings:

• The patient experienced a rare cardiovascular side effect, specifically second-degree heart block.
• The atrioventricular block was directly associated with donepezil treatment.
• Discontinuation of donepezil resulted in the complete resolution of the heart block.

Implications:

• This case highlights the potential for donepezil to induce cardiac conduction abnormalities even in patients without prior cardiac disease.
• Prescribers should be vigilant for cardiovascular side effects, including heart block, in patients receiving donepezil.
• Further investigation into the cardiac safety profile of donepezil, particularly in susceptible populations, may be warranted.