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. Making sure that you are exercising regularly and eating a healthy diet full of fruits and vegetables can help improve your overall health and circulation, helping to make the effects of Viagra or Sildenafil even more pronounced. Erectile dysfunction for sildenafil By mouth Adult Initially 50 mg, to be taken approximately 1 hour before sexual activity, adjusted according to response to 25— mg max. Keep from freezing. From Mayo Clinic to your inbox Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. · The effects may be increased because of slower removal of the medicine from the body. Leukemia (blood related cancer) or. Multiple myeloma (blood related cancer) or. Sickle-cell anemia (blood disorder)—Sildenafil should be used with caution in these patients as problems with prolonged erection of the penis may occur.  · Adults 65 years of age and older—25 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be . Sildenafil citrate is a white to off-white crystalline powder with a solubility of mg/mL in water and a molecular weight of VIAGRA is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg, and mg of sildenafil for oral administration.