The former restaurant manager, who played semi-professional ice hockey during the 28 years he lived in Canada, told the Evening News in 2005 how being a guinea pig for taking Viagra to treat PH saved his life.

It is now four-and-a-half years since Grant began taking Revatio - a drug with the same active ingredients as Viagra. Since then it has been licensed to treat other patients with PH, including a fellow PH sufferer, who lives just a mile from Grant.

Udenafil was approved by the Korean FDA in November 2005 and launched by Dong-A Pharmaceutical in Korea under the brand name Zydena® in late December 2005 as the fourth entrant to the ED market.

Cialis, which has been distributed to 5,000 Chinese pharmacies this month, is effective for up to 36 hours, longer than rival drugs on the market, Lilly says.