Three weeks after the FDA allowed Wyeth to begin marketing what the drugmaker calls a reformulated version of its heartworm med on a restricted basis, a pair of dogged Congressional reps want the agency to justify its decision. ProHeart 6, you may recall, was yanked four years ago after being linked to an unusually high rate of deaths and serious side effects. The episode spoke poorly of the FDA, though. In 2003, an FDA vet examined a growing number of adverse reactions, prompting the withdrawhttp://www.pharmalot.com/2008/06/congress-...