European officials have approved a once-daily version of impotence pill Cialis...

LONDON, June 25 (Reuters)

The drug's maker, Eli Lilly and Co. (LLY.N: Quote, Profile , Research), said on Monday that the green light from the European Commission meant Cialis was the first erectile dysfunction medicine cleared for continuous use.

Until now, drugs such as Cialis and Pfizer Inc.'s (PFE.N: Quote, Profile , Research) rival product, Viagra, have been taken as needed.

The new low-dose formulation of Cialis, by contrast, is taken all the time, which eliminates the need to plan sex within a limited timeframe. It is aimed at men who anticipate sexual activity at least twice a week.

Lilly plans to start launching the once-daily version in certain European countries in the second half of 2007.

Cialis generated worldwide sales of $266 million in the first quarter of 2007, up 19 percent on a year earlier. The once-daily version could help Lilly differentiate its medicine from competitors, according to industry analysts.