Some people may also have ringing in their ears tinnitus or dizziness. You’ll soon start receiving the latest Mayo Clinic health information you requested in your inbox. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. This is important for your overall health and safety, as certain medications can negatively interact with each other or cause existing conditions to worsen. Ask your doctor if you have any questions. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes.Sildenafil oral tablet is used to treat erectile dysfunction (ED). It’s also used to treat pulmonary arterial hypertension (PAH). What is sildenafil? Sildenafil is a prescription drug. It comes in. In the United States, chewable ED tablets are available only through the online subscription service BlueChew. According to the company site, it makes chewable versions of sildenafil. Viagra takes around 30 minutes to become effective and lasts about 4 hours. Cialis lasts much longer — up to 36 hours in some cases. Stendra can start doing its thing in as little as 15 minutes.