It is quite normal for a man to not obtain or maintain a penile erection at times. However, frequent episodes can be a sign of an underlying disease or disorder. If you are suffering from erection problems frequently, it is better to consult a physician. A doctor usually prescribes erectile dysfunction medications if you do not have any other health issues. Sildenafil citrate, Tadalafil, Vardenafil, and Avanafil are medications that are useful for treating erectile dysfunction. The generic versions of these medications are popular and thus widely used. Silvitra and Filitra are found to be effective generic medications useful for treating impotence. It is actively composed of Vardenafil, a powerful PDE-5 inhibitor. The FDA approved Vardenafil in 2003 for treating impotence. It is a prescription-based, non-habit-forming medication. It is to be taken at least 30 to 60 minutes before having sexual intercourse. Consume it only once in 24 hours. Do not crush, break or chew the oral tablets. They are to be taken as a whole.