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.
Heroin and prescription drug use can slow or disrupt the heart rate to the point of death. Cocaine, methamphetamine, ecstasy and amphetamines can cause life-threatening effects, including an irregular heartbeat, increased blood pressure, stroke and cardiac arrest.