Quoting anonymous company sources, the magazine reported that the firm expected European Union approval for a cheaper, generic version of the wonderdrug early next year.

The US drug giant Pfizer’s patent on the medication is due to expire in 2013. It has been a blockbuster drug for pharmaceuticals giant, earning the company about €350 million a year.

However, competitors have already eaten into Pfizer’s market share.

Although Sildenafil citrate, which is the generic name for Viagra, is most commonly used for curing erectile dysfunction, it can also be used to treat pulmonary hypertension and altitude sickness, and is sometimes used by athletes to increase blood flow to muscles.

The move by Düsseldorf-based Ratiopharm is part of chief executive Oliver Windholz’s effort to lift the company’s sales from €1.6 billion a year to €2.4 billion by 2014.