How To Use Levitra Tablets? Levitra 20 mg Tablets are available in 5,10, and 20 mg dosages. Men who are facing erectile dysfunction problems can take a tablet once a day with or without food. Take this dose 30 minutes before the sexual activity. The maximum amount of Levitra that can be taken is 20 mg, depending upon the person’s response. Take them after 24 hours from the first dose, don’t take them twice