Antibiotic maker ViroPharma (VPHM) is making news today and none of it is good for the company’s investors. Not only does ViroPharma now face generic competition for its lead product Vancocin the US Federal Trade Commission is investigating whether the company “engaged in unfair methods of competition” when it sold the powerful antibiotic. Watson Pharmaceuticals (WPI) got the green light to sell generic Vancocin in the US despite ViroPharma’s efforts to block approval. Shares of ViroPharma fell 17% to $23.84 in midday trading Tuesday. The stock is still up more than 20% over the past six months. Watson fell ...