India's pharmaceutical companies are rushing to launch drugs for the treatment of erectile dysfunction in men, in an attempt to beat the January 1, 2005, deadline when the product patents regime comes into force in India.

Generic companies can market chemical equivalents of the drug, Tadalafil, till January 1, 2005, because the drug was registered after 1995 by Eli Lilly, the company that has a patent for it. Pfizer hasn't introduced Viagra in India.

After Ranbaxy and Ajanta Pharma launched generic versions of this drug early this year, a slew of pharmaceutical companies, including Zydus Cadilla, Kopran and Shreya Life Sciences, have hit the market with generic versions of Tadalafil.

Others like Glenmark, Natco and Matrix Laboratories are understood to have applied to the drug controller's office for marketing the active pharmaceutical ingredient of the same drug.

The erectile dysfunction drug market is worth Rs 80 crore (Rs 800 million) and it is growing by 41 per cent a year. "That's why it is a lucrative business," a Kopran spokesperson said.

Eli Lilly, whose drug, Cialis, is its erectile dysfunction segment drug, according to sources, had applied for an exclusive marketing right in India. However, it is yet to get a decision from the Indian Patent Office.

While Tadalasia is Ajanta Pharma's brand, Ranbaxy Laboratories markets it under the brand name Forzest, and Kopran's drug is called Nialis.