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.
Occasionally epinephrine may be added to a nerve block. Epinephrine causes vasoconstriction of the blood vessels near the injection site. This causes decreased uptake of local anesthetic into the vasculature, allowing the block to work for a longer duration. Opioids are rarely used in a nerve block.