Vardenafil

Overview
Vardenafil (INN) 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 (Bayer AG).

History
Vardenafil was co-marketed by Bayer Pharmaceuticals and GSK under the trade name Levitra. As of 2005, the co-promotion rights of GSK on Levitra have been "transferred back" to Bayer in many markets outside of the United States. In Italy, Bayer markets the product as Levitra and GSK markets the product as Vivanza. Due to European Union trade rules, parallel imports may result in the Vivanza branded packs being seen alongside Levitra packs in pharmacies in other EU member states.

Clinical use
Indications and contraindications are as for other PDE5 inhibitors. As a PDE5 inhibitor, 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.

Adverse drug reactions
More common adverse drug reactions (ADRs) are as per other PDE5 inhibitors and are listed on that page.

Common vardenafil-specific ADRs include: nausea. Infrequent ADRs include: abdominal pain, back pain, photosensitivity, abnormal vision, eye pain, facial oedema, hypertension, palpitation, tachycardia, arthralgia, myalgia, rash, itch, priapism. (Rossi, 2004)

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. Health Canada (2006)

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.

Drug interactions
Products containing vardenafil should not be used by individuals who are taking any nitrate medication because combining these products could result in the development of potentially life-threatening low blood pressure.

Dose forms
It is available in 2.5 mg, 5 mg, 10 mg, and 20 mg doses in round orange tablets. The normal starting dose is 10 mg (roughly equivalent to 50 mg of sildenafil). Vardenafil should be taken 25–60 minutes prior to sexual activity, with a maximum dose frequency of once per day. In some territories, such as the UK, only certain doses may be available, i.e. 5 mg, 10 mg, and 20 mg.