Keep from freezing. Other conditions that may disqualify you from an ED prescription include a history of stroke, kidney or liver disease, cancer, diabetes, or a bleeding disorder. Most erectile dysfunction medications belong to the drug class known as PDE5 inhibitors , which help relax the muscles and increase blood flow to allow for a full erection. It’s available in 50 mg, mg, and mg tablets. Privacy: Confirm that your personal data and payment details are confidential.Updated on April 21, Key takeaways: Viagra (sildenafil) is a prescription medication used to treat erectile dysfunction. Headache, flushing, and upset stomach are common .  · For oral dosage forms (suspension or tablets): Adults—20 milligrams (mg) 3 times a day. Your doctor may adjust your dose as needed and tolerated. However, the . sildenafil citrate or viagra Savings, Coupons and Information. | SILDENAFIL (sil DEN a fil) treats erectile dysfunction (ED). It works by increasing blood flow to the penis, which .