Viagra Dosage/Direction for Use

Sildenafil tablets are for oral administration.
Use in adults: For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg. The maximum recommended daily dose is 100 mg. The maximum recommended dosing frequency is once per day.
Use in patients with impaired renal function: Dosage adjustments are not required in patients with mild to moderate renal impairment (creatinine clearance = 30 - 80 mL/min).
Since sildenafil clearance is reduced in patients with severe renal impairment (creatinine clearance <30 mL/min), a 25 mg dose should be considered.
Use in patients with impaired hepatic function: Since sildenafil clearance is reduced in patients with hepatic impairment (e.g., cirrhosis), a 25 mg dose should be considered.
Use in patients using other medications: Given the extent of the interaction with patients receiving concomitant therapy with ritonavir (see Interactions), it is recommended not to exceed a maximum single dose of 25 mg of sildenafil in a 48-hour period.
A starting dose of 25 mg should be considered in patients receiving concomitant treatment with the CYP3A4 inhibitors (e.g., erythromycin, saquinavir, ketoconazole, itraconazole) see Interactions.
In order to minimize the potential for developing postural hypotension, patients should be stable on alpha-blocker therapy prior to initiating sildenafil treatment. In addition, initiation of sildenafil at lower doses should be considered (see Precautions and Interactions).
Use in children: Sildenafil is not indicated for use in children (<18 years old).
Use in elderly men: Dosage adjustments are not required in elderly patients.