It continues to work for up to 4 hours, although its action is usually less after 2 hours. Do not use more of it and do not use it more often than your doctor ordered. Lifestyle and home remedies For many people, erectile dysfunction is caused or worsened by lifestyle choices. You also may have bruising on your penis. If you are taking sildenafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire. Write down key personal information, including any major stresses or recent life changes.For treatment of erectile dysfunction: For oral dosage form (tablets): Adults up to 65 years of age—50 milligrams (mg) as a single dose no more than once a day, 1 hour before . The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 . Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Sildenafil treats PAH by .