Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine. Socio-demographic characters of sildenafil users in Gondar town, Keep out of the reach of children. Adverse Effects Warnings and Precautions Sildenafil has systemic vasodilatory effects and, as such, should be prescribed with caution to patients who may be sensitive to such blood pressure changes, such as patients with left ventricular outflow obstruction and impaired autonomic control of blood pressure. Do not use a kitchen teaspoon as it will not measure the right amount. · 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. 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 . Text Download Email With the VIAGRA Savings Card, eligible patients may save 50% on . Like Viagra, certain forms of sildenafil are approved to treat ED in males* ages 18 years and older. For example, sildenafil mg, mg, and mg tablets are approved for this use.