Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. Such patients must not apply any out-of-pocket expenses incurred using this Savings Offer toward any government insurance benefit out-of-pocket spending calculations, such as Medicare Part D true out-of-pocket TrOOP costs You are responsible for reporting use of this Savings Offer to any private insurer, health plan, or other third party who pays for or reimburses any part of the prescription filled using this Savings Offer, as may be required. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and site usage information with other information we have about you. Medicines that you take by mouth are called oral medicines. Some people may also have ringing in their ears tinnitus or dizziness.For treating ED specifically, Viagra is the well-known brand-name version of this drug. Many factors can influence how long Viagra takes to start working. In general, Viagra takes about 30 minutes.  · Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. Viagra alternatives range from medical options like Cialis and Levitra to natural methods like acupuncture and even therapy. We break them all down here. When you think of erectile dysfunction.