Common side effects may include headache, flushing of the skin, and lightheadedness.[1] Other side effects may include fainting, lose of bladder control, low blood pressure, and nausea.[1] Large doses may result in methemoglobinemia.[1] Tolerance to its effects may occur with withdrawal after it is stopped.[2] It is a yellow liquid with a smell that has been described as fruity.[4][2] Medically it works by dilating blood vessels.[2]