Potential cardiotoxic reaction involving rivastigmine and beta-blockers: a case report and review of the literature.

We report a case of potential cardiovascular toxicity including syncope, bradycardia, and ECG pauses associated with the use of rivastigmine and atenolol. A 65-year-old African American female with a medical history of dementia, hypertension, seizure disorder, stroke, and peripheral vascular disease was admitted to the hospital with shortness of breath and syncope. She was witnessed to have experienced a presyncopal episode followed by a true syncopal episode in which she was unresponsive for 20-30 s. On day two of hospital stay, the patient's ECG showed a sinus bradycardia with a heart rate in the 40 s and sinus pauses greater than 2 s in duration. Atenolol was immediately discontinued, with a continuance of the bradycardia despite one missed dose. The potentially toxic combination of rivastigmine and atenolol was then identified as a plausible causative factor of this patient's syncope and was subsequently discontinued. This patient's Naranjo adverse reaction probability score was five, which indicates a probable association between syncope and bradycardia with the combination of rivastigmine and atenolol [13]. Following the discontinuation of rivastigmine, the ECG pauses resolved and the patient's heart rate returned to normal levels. The patient did not experience any further dizziness or syncope. A 65-year-old female developed syncope and subsequent ECG pauses with sinus bradycardia after being treated with rivastigmine for dementia. Atenolol may have further compounded this toxic effect by its pharmacodynamic mechanisms.