If you have an erection that lasts for more than 4 hours, you should go to the nearest hospital emergency department. You can get a prescription online following a quick and easy visit with a member of our clinical team. The design was a randomized, double blind, cross-over study with four treatments: vardenafil 5 mg or placebo administered simultaneously with the alpha-blocker and vardenafil 5 mg or placebo administered 6 hours after the alpha-blocker. There is no clinical evidence of any additive prolongation of the bleeding time when vardenafil is administered with aspirin. If you have ever had an allergic reaction to a medicine.Key facts. Vardenafil (Levitra) is a medicine used to treat erectile dysfunction (ED, also called impotence). Vardenafil works by helping to relax the blood vessels in the penis, allowing blood to flow more easily and making it easier to get an erection. Vardenafil should be taken about 30 minutes before planned sexual activity. Levitra. Used for Erectile Dysfunction. Vardenafil is a first-choice medication for erectile dysfunction (ED). It’s no longer sold under the brand name Levitra, but it’s available as generic tablets and orally disintegrating tablets (ODTs). Common side effects of vardenafil include headache, flushing, and stuffy test1.rug: walmart. detected when LEVITRA 20 mg was dosed 24 hours before NTG. (See Figure 2.) Figure 2: Placebo-subtracted point estimates (with 90% CI) of mean maximal blood pressure and heart rate effects of pre-dosing with LEVITRA 20 mg at 24, 8, 4, and 1 hour before mg NTG sublingually.