Never take an extra dose to make up for a forgotten one. If you already use medicine for high blood pressure hypertension , sildenafil could make your blood pressure go too low. Dosing The dose of this medicine will be different for different patients. Keep from freezing. This medicine has been approved in the United States to treat premenopausal females who have low sexual desire. Store mixed oral liquid in the refrigerator.1 day ago · Hims is a telehealth company that provides both prescription and over-the-counter generic and brand-name medications. The brand focuses mainly on five medications, including Viagra, that have. Sildenafil (Viagra) is a medicine used to treat erectile dysfunction (ED, also called impotence). Sildenafil works by helping to relax the blood vessels in the penis, allowing more blood to flow in and cause an erection. You should take sildenafil about an hour before planned sexual activity, so it has time to work. It’s also known as ED or impotence. It happens when not enough blood flows to the penis, preventing an erection. The frequency increases with age, affecting about 50% of men over age 40*; however younger men may also experience ED. Some guys with ED find it difficult to either get or keep an erection every time they try to have sex.