The bloodshot appearance is due to the irritation and dilation of the surface blood vessel in the eye. Other symptoms can accompany the red appearance, like itching, soreness, discharge and even blurred vision. These symptoms could indicate a more serious problem.
The list of possible medications or substances mentioned in sources as possibe causes of Heart block includes: 1  Beta-adrenergic blockers. 2  Digitalis. 3  Flecainide. Flecatab. 4  Flumadine. Quinidine. 5  Rimantidine. Tambocor.
Prescription and over-the-counter (OTC) drugs that can cause arrhythmias include tricyclic antidepressants (TCAs), antihistamines, and beta blockers. Additionally, illegal drugs such as cocaine and methamphetamines, and stimulants including caffeine and nicotine, can cause arrhythmias.