ProHeart 6, a twice-a-year time-released heartworm medication used to prevent the parasite in millions of dogs, was recalled Friday at the request of the Food and Drug Administration (news - web sites) after thousands of animals suffered adverse reactions. ProHeart 6 was the first, and only, product approved by the FDA (news - web sites) to be administered once every six months to treat heartworm disease in dogs. Its active ingredient, moxidectin, has been administered without problem to horses and cattle. The time-released version caused few problems when given to dogs at higher doses in clinical trials. Health and safety problems quickly cropped up, however, when ProHeart 6 was used to treat dogs after receiving FDA approval.
