Postpone periods medicine sildenafil is applied for the treatment of erectile dysfunction (impotence) in men and pulmonary arterial hypertension. The contents of this website are for informational purposes only and not intended to be a substitute for professional medical advice, diagnosis, or treatment. Please seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition. Do not disregard professional medical advice or delay in seeking it because of something you have read on this website. 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.