Vardenafil

Vardenafil (INN) is a PDE5 inhibitor used for treating impotence (erectile dysfunction) that is sold under the trade name Levitra (Bayer AG, GSK, and SP).

History
Vardenafil was co-marketed by Bayer Pharmaceuticals, GSK, and SP under the trade name Levitra. As of 2005, the co-promotion rights of GSK on Levitra have been returned to Bayer in many markets outside the U.S. In Italy, Bayer sells vardenafil as Levitra and GSK sells it as Vivanza, thus, because of European Union trade rules, parallel imports might result in Vivanza sold next to Levitra in the EU.

Clinical use
Vardenafil's indications and contra-indications are the same as with other PDE5 inhibitors; it is closely related in function to sildenafil citrate (Viagra) and tadalafil (Cialis). Structurally, 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.

Beyond its indications for erectile dysfunction, vardenafil may be effective in the treatment of premature ejaculation, where it may significantly increase the time from vaginal penetration to ejaculation.

Adverse drug reactions
The common, adverse drug reactions (side effects) are the same as with other PDE5 inhibitors. The frequent vardenafil-specific side effect is nausea; the infrequent side effects are: abdominal pain, back pain, photosensitivity, abnormal vision, eye pain, facial oedema, hypotension, palpitation, tachycardia, arthralgia, myalgia, rash, itch, and priapism. (Rossi, 2004)

One possibly serious, but rare, side effect with vardenafil is heart attack. Also in rare cases, vardenafil use may cause priapism, a very painful emergency condition that can cause impotence if left untreated.

On 18 October 2007, the U.S. Food and Drug Administration (FDA) announced that a warning about possible deafness (sudden hearing loss) would be added to the drug labels of Vardenafil, and other PDE5 inhibitors.

Drug interactions
Vardenafil, as with all PDE5 inhibitors, should not be used by men taking nitrate medications, because combining them with vardenafil might provoke potentially life-threatening hypotension (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 1 to 2 hours 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.