Long-Lasting Anti-Impotence Pill Approved

Tadalafil, trademarked as Cialis, was developed by US-based pharmaceutical companies Lilly and Icos, and should go on sale in Europe early in 2003. Lilly and Icos hope to gain approval next year to market the drug in the US.

The European green light followed scrutiny of results of more than 60 trial studies, including final efficacy studies on over 1000 men. These trials showed the drug achieves its effect in as little as 16 minutes and last between 24 and 36 hours.

Cialis works in the same way as Viagra: by inhibiting an enzyme called PDE5, which is involved in regulating blood flow. This allows more blood to flow to the penis.

But Cialis is reportedly faster to enter the blood stream, and persists for longer. Viagra, manufactured by Pfizer, takes an average of about one hour to work. Its effects typically last up to a maximum of about twelve hours.

About five per cent of trial patients taking Cialis reported side effects including headaches and heartburn. Viagra is not recommended for men with heart conditions, because it can cause a drop in blood pressure, and Cialis is likely to carry similar warnings.

An estimated 31 million men in Europe and 152 million worldwide suffer from erectile dysfunction. Pfizer says that 20 to 25 per cent of US men with the condition seek treatment, compared with only 10 to 15 per cent of European men.

US business analysts think the market for anti-impotence drugs will expand - but largely due to sales of Cialis.

A fast-acting anti-impotence drug called Uprima, which works in a different way to Viagra and Cialis, is already on sale in Europe. And GlaxoSmithKline and Bayer AG have also developed a Viagra rival called Levitra, which has been submitted for approval in Europe and the US.

The Original Story from: www.newscientist.com