Sildenafil has not been studied with other medication using for treat of erectile dysfunction. Presently, using them together is not recommended .
Use sildenafil exactly as directed by your family doctor . Do not use more of it and do not use it more often than your family doctor ordered. If too much is using, the risk of side effects is increased.
If you experience a prolonged or painful erection for 4 hours or more, contact your family doctor immediately. This condition may require prompt medical treat to prevent tissue damage of the penis and possible permanent impotence.