Cialis, Viagra and Levitra are the only oral drugs approved by the FDA to treat impotence ( erectile dysfunction ). They work by increasing the blood flow into the penis so that when a man is sexually stimulated, he can get an erection.
What Are the Differences Between Cialis, Viagra and Levitra?

Cialis, Viagra and Levitra work by a similar mechanism to cause an erection. Some differences are in how long the drug works and how quickly the effect apears. Levitra works a little longer than Viagra. Both take effect in about 20 minutes. With Levitra, the effects last for about 4 hours. With Viagra, the effects last approximately 5 hours.

Cialis works a bit faster (within 14 minutes), and the effects last much longer -- up to 35 hours in some cases.

Watch the video below to find out more information about these drugs :

Viagra Vs Cialis Vs Levitra - Viagra and Cialis Comparison