Which Is Better Viagra Or Levitra? However, because it is the generic version of the medicine, rather than the brand, Sildenafil is considerably cheaper. Levitra will last for a similar amount of time as Viagra (four to six hours). The main difference to Viagra is that Levitra tends to be less affected by food or alcohol so can be taken with meals How long does it take for levitra to take effect? about 30 minutes How long does it take erectile dysfunction medication to work? Viagra and Levitra take about 30 minutes to work, and the effects last for about 4 hours after you take the pill. You should take Cialis at least 2 hours before you plan to have sex.