Vardenafil is the active ingredient in the medicine vilitra 40mg. Vardenafil is a member of the phosphodiesterase type 5 (PDE5) inhibitors pharmacological class. Men with erectile dysfunction (ED) are the main patients for this medication. Vardenafil works by preventing phosphodiesterase type 5, an enzyme that breaks down cyclic guanosine monophosphate (cGMP), from doing its job.