Familiarize yourself with the ingredients before taking Levitra to make sure none of them will cause an allergic reaction. If you experience any symptoms associated with allergies such as difficulty breathing, hives, swollen tongue etc., stop using the medication and seek urgent medical help.
Common side effects of taking Levitra include headache, flushing, skin rash, nausea, pain in the abdomen, vomiting, bloating, heartburn, rapid decrease in the blood pressure, stuffy nose, back pain, diarrhea, upset stomach, memory problems, and changes in color vision. In case of an erection that lasts longer than four hours, as well as if any side effects persist, consult your doctor.
Note that this list does not include all possible side effects. Other side effects might occur depending on individual health conditions. Consult your doctor for more information.