Men aged 18 and up who suffer from erectile dysfunction, often known as impotence, are prescribed Levitra 5mg if they are unable to obtain or maintain a strong enough erection for fulfilling sexual engagement. Levitra requires sexual excitement in order to work.In general, Levitra causes an erection that lasts significantly longer and works more quickly. It is also important to note that both require foreplay to function properly, as they only work when you are sexually stimulated.