Vardenafil (Molecule of the Month for April 2008)
Vardenafil is a PDE5 inhibitor used in the treatment of erectile dysfunction. It can assist men with this disorder in achieving and maintaining an erection during sexual activity. It is commonly marketed under the trade name Levitra (sold by Bayer AG).
Vardenafil is closely related in both function and marketing to sildenafil (Viagra) and tadalafil (Cialis). Structurally, the vardenafil molecule differs from sildenafil by only a methyl group and the position of one nitrogen atom in its structure. It has a relatively short effective time, comparable to sildenafil.
Headache is a very common adverse effect, occurring in >10% of patients. Other common ADRs include: dizziness, flushing, dyspepsia, nasal congestion or rhinitis. The use of products containing vardenafil has also been associated with serious side-effects which include serious cardiac events such as heart attacks. In rare cases, the use of vardenafil may result in penile tissue damage and permanent loss of potency. On October 18, 2007, the FDA announced that a warning about possible sudden hearing loss would be added to the drug labels of vardenafil and other PDE5 inhibitors.
Update by Karl Harrison
(Molecule of the Month for April 2008 )