The first thing I would ask, what temperature did you ferment it at? High fermentation temps (75+) can lead to the production of fusel alcohols and other compounds that could be described as medicinal. Correct me if I'm wrong, but this is an extract recipe right? Did you steep some specialty grains with it? If so, did you leave the grains in the pot during the boil? I only ask because doing that will extract tannins from the grain husks that can lead to an astringent (medicinal) flavor. Like what happens to a cup of tea if you leave the teabag in too long.