The adverse effects of nitroglycerin are generally mild and insignificant, but improper use of nitroglycerin can lead to the following side effects: 1. flushing of the skin on the head and neck, which is caused by direct dilation of the peripheral blood vessels. 2. hypotension, which is caused by excessive use of the drug, resulting in lower blood pressure. 3. blurred vision, which is caused by the dilation of the blood vessels in the eye due to nitroglycerin, increasing intraocular pressure and causing blurred vision. 4. This phenomenon is caused by the direct dilatation of the peripheral blood vessels, resulting in lower blood pressure, which can lead to hypotension. 3.