Atrioventricular Block Caused by Carteolol Eye Drops Administered to Unilateral Eye or Bilateral Eyes: A Case Report.

Ophthalmic beta-blocker carteolol can rarely cause cardiovascular effects such as bradycardia, heart block, and hypotension. We report a case of carteolol eye drops induced atrioventricular (AV) block. A 76-year-old man with type 2 diabetes developed exercise-induced second-degree AV block, which improved after discontinuing carteolol eye drops in the unilateral eye. Six months later, third-degree AV block recurred due to inadvertent reuse of carteolol eye drops in bilateral eyes despite its prohibition. A seven-day patch electrocardiogram (ECG) monitor showed AV conduction returned to a 1:1 ratio after discontinuation of eye drops. The pacemaker implantation was deferred, and he is currently under close follow-up. Depending on the amount administered to a unilateral eye or bilateral eyes, topical carteolol eye drops can cause second- or third-degree AV block.