Shanghai-listed Guangzhou Baiyunshan Pharmaceutical Holdings Co announced on Sept 18 that it would start selling a generic erectile dysfunction medicine, sildenafil citrate, in late October.

The medicine is a crystalline compound that works by inhibiting the breakdown of enzymes that leads to loss of erection.

Baiyunshan, a subsidiary of State-own enterprise Guangzhou Pharmaceutical Holdings, is the first domestic pharmaceutical company that has successfully got approval, since US-based Pfizer Inc’s patent for the medicine–-known under the brand name Viagra–- expired in China in May.

Statistics show that 52 percent of adult males in the US suffer from the disorder, and although there is no reliable national epidemiological investigation on the prevalence of the disorder in China, Guo Yinglu, a member of the Chinese Academy of Engineering and one of China’s leading urological surgeons, believes the figure would be more or less the same.

That means a potentially huge market for ED medicines, which Pfizer currently accounts for nearly half, followed by Eli Lilly and Co and Bayer AG, he said.