Levitra, the new impotence therapy co-marketed by GlaxoSmithKline and Bayer has captured 50 per cent of the share of new prescriptions in the erectile dysfunction market in the US, says ImpactRx, a pharmaceutical promotion research company.

This suggests Levitra (vardenafil) has already won a clear edge over the current block-buster therapy for erectile dysfunction—Pfizer’s Viagra, that too in less than a month

The data collected by this Mt. Laurel, N.J. based firm also show that sales representatives from GlaxoSmithKline and Bayer are talking to doctors about Levitra 50 per cent more than sales representatives from Pfizer are speaking about Viagra.

With 11,000 sales representatives, Pfizer generally dominates marketing among physicians in almost every category of drugs that is important to the company. But GlaxoSmithKline has 8,000 sales representatives itself, and Bayer has 3,000 more.

The Pfizer sources, however, dismissed the findings saying the data is grossly inconsistent with the audit data that the company use, which shows that Viagra still dominates the category.

Levitra had benefited from "false claims and public relations in which they inaccurately state that Levitra works faster and is better, neither of which is true," they say.

Levitra is the most important drug introduction for either company in years.

According to a recent news release by Bayer/GSK, ninety per cent (90%) of men reported improved erections. Each Levitra pill may work in as quickly as 25 minutes and may work for up to 24 hours. Levitra acts in the same way as Viagra, by blocking an enzyme called phosphodiesterase-5, or PDE-5.

Analysts point out that the secret of Levitra's extraordinary success is an unapologetic push for recreational use through ad blitzkrieg.

GSK and Bayer, admit that they are focusing on men who may have successful sexual relationships but who simply want to improve the quality or duration of their erections.

However, industry observers prefer to be more cautious. According to them it's way too early to make a decision as to whether Levitra will be preferred over Viagra in the long run. Moreover, another competitor from Eli Lilly—Cialis which claims a much longer efficacy of 36 hours (while Viagra and Levitra work for four to five hours.) is under final review with US FDA and is soon to hit market.