Levitra can also interact with alpha-blockers, a type of medications used to treat hypertension high blood pressure and symptoms of benign prostatic hyperplasia BPH. Always talk to your doctor about the risks and benefits of any treatment. Priapism is a serious medical issue, meaning that if you get an erection that lasts for four hours or longer after using Levitra, you should seek medical assistance immediately. Use the medicine exactly as directed. This medicine also works best when you take it an hour before sex on an empty stomach.Common ones include: Flushing of the skin. Headache. Upset stomach. Visual changes, such as blue tinge to vision, sensitivity to light or blurred sight. Stuffy or . Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome): Back pain; Facial flushing or redness; Headache; Muscle . Common side effects of Levitra include facial flushing (reddening), headaches, stomach upset, diarrhea, flu-like symptoms, and nausea. Serious side effects of Levitra include .