New erection drugs sildenafil is applied for the treatment of erectile dysfunction (impotence) in men and pulmonary arterial hypertension. Many people using this medicine do not have serious side effects. Most usual side effects of Apcalis are facial flushing (reddening), headaches, stomach upset, diarrhea, flu-like symptoms and nausea. In more rare cases low blood pressure, blurred vision and changes in color vision, and abnormal ejaculation may occur. Prolonged erections or priapism (painful erections lasting more than 6 hours) are also possible. If your erection is longer than 4 hours, seek for immediate medical help as it may permanently damage your penis. Aggravation of heart problems in patients with pre-existing heart disease using Apcalis was reported.