It's a very nice design. Orange is difficult to use as a primary site color - it's generally very aggressive, which works for me, but considering your target audience, you may want to soften this a bit.
Fixed size fonts will bother IE users, especially if you're targeting pharmeceutical professionals. They will tend to be older than the average visitor and will rely on being able to resize text to a much greater extent. Of course, this should be done regardless of the target market, but this is a classic example of a site that would benefit from it. FWIW, I enlarged your fonts to 14pt. in Opera, and the site looked quite nice. It seems the design itself doesn't suffer in the least, so you won't need to redesign anything. Just change those fixed sizes to %, em, or ex and you'll be in business.