Store mixed oral liquid in the refrigerator. It is not known if the medicine is safe for use in these patients. Do not take it more than 3 times a day. Taking sildenafil alone will not cause an erection. Dose-related visual disturbances occurred more frequently at toxic levels, while blood pressure changes showed a low correlation.Viagra comes as an oral tablet in different dosages. Discuss with your doctor what’s an appropriate dose for you. For daily use, Goldstein said, the generic form, sildenafil, comes in mg tablets. Although erectile dysfunction (ED) may be an upsetting diagnosis for some, many people find their condition is treatable with Viagra — sometimes called the “little blue pill” — and it’s generic. This means that 4 hours after you take a dose, your body has cleared half of the dose. In most cases, it takes about 5 half-lives for your body to completely remove a drug from your system. So.