Levitra (vardenafil) is a highly-efficient prescription medication used by people unable to have sex due to some problems with erection. Such problems may include repeated inability to achieve erection of any firmness or being able to hold it for very little time. You don’t have to get worried if you experience some or any of the following minor side effects of Levitra: heartburn, headache, flushing, upset stomach, stuffy or runny nose, and flu-like symptoms. Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately: hoarse voice, rash and hives, ringing in the ears, blurred vision, loss of vision or hearing, prolonged and painful erection, dizziness, swelling, trouble breathing, or difficulty swallowing.