It has been a busy year for Pfizer, the maker of the ubiquitous erectile-dysfunction treatment, Viagra. The company spent the fifth birthday of its banner pill combating the first rivals to its worldwide monopoly. Bayer AG/GlaxoSmithKline's Levitra and Icos/Eli Lilly's Cialis have already started snatching up international market share (the latter awaits approval in the US). The coverage suggests that erectile dysfunction has a significantly bigger market than Viagra has tapped.

Most frequent messages 1. Viagra's five-year dominance faces serious competition 2. Viagra ...