Editing Vardenafil (section)

==Medical uses==
Vardenafil's indications and contraindications are the same as with other PDE5 inhibitors; it is closely related in function to [[sildenafil]] citrate (Viagra) and [[tadalafil]] (Cialis). The difference between the vardenafil molecule and sildenafil citrate is a [[nitrogen]] atom's position and the change of sildenafil's [[piperazine]] ring [[methyl group]] to an [[ethyl group]]. Tadalafil is structurally different from both sildenafil and vardenafil. Vardenafil's relatively short effective time is comparable to but somewhat longer than sildenafil's. Despite the structural differences between vardenafil and sildenafil, they both show similar ocular side effects due to their similar selectivity overlap with PDE6, an enzyme found in the eye.<ref name="selectivity">{{cite journal | vauthors = Bischoff E | title = Potency, selectivity, and consequences of nonselectivity of PDE inhibition | journal = International Journal of Impotence Research | volume = 16 | issue = Suppl 1 | pages = S11–S14 | date = June 2004 | pmid = 15224129 | doi = 10.1038/sj.ijir.3901208 | doi-access = free }}</ref>

Beyond its indications for erectile dysfunction, vardenafil may be effective in the treatment of [[premature ejaculation]], where it may significantly increase the time from penetration to ejaculation.<ref name="IJIR Premature Ejaculation">{{cite journal | vauthors = Aversa A, Pili M, Francomano D, Bruzziches R, Spera E, La Pera G, Spera G | title = Effects of vardenafil administration on intravaginal ejaculatory latency time in men with lifelong premature ejaculation | journal = International Journal of Impotence Research | volume = 21 | issue = 4 | pages = 221–7 | date = July 2009 | pmid = 19474796 | doi = 10.1038/ijir.2009.21 | doi-access =  | s2cid = 26078130 }}</ref>