Viagra (Sildenafil)
Purpose of Medication and Method of Action
Viagra is used to treat male impotence. It acts by inhibiting the production of a biochemical called nitric oxide. The production of nitric oxide following completion of ejaculaton results in an outflow of blood from the penis and loss of an erection. This inhibition of nitric oxide production results in a reduction of blood outflow from the penis and a more easily developed erection. The erection, once developed should last for 1-2 hours.
Side Effects
Headache or a sensation of "fullness in the head", facial flushing, and abdominal pain are the most common. A change in the ability to distinguish blue and green colors may also occur. These side effects are self-limiting and should disappear after a few hours.
Drug Interactions
None reported
Cautions and Contraindications
Patient also taking oral nitroglycerin products may experience a significant reduction in blood pressure and thus in those circumstances, Viagra should by used with great caution. Also, individuals with a history of high blood pressure or heart disease may be at great risk for severe life-threatning reactions.
Usual Dose
The usual dose is 50-100 mg 1/2 to 4 hours prior to intercourse although the average time to take prior to intercourse is 1 hour. The dose should not exceed 100 mg per day.
Patient Medication Information
These information sheets do not list all known side effects of the medications, only the most common side effects. For a complete list of side effects please contact your local pharmacy or the actual drug manufacturing company.