Approved changes to the RiskMAP for ProHeart 6 (moxidectin) now allow dogs to receive their first injection of the heartworm preventive after age 7, the manufacturer, Zoetis Inc., reported today. ProHeart 6, effective for six months at a time, previously was permitted for first-time use in dogs ages 6 months to 6 years. Removing the restriction on older dogs followed a 4½-year safety review that found age was not a reliable indicator of when a dog may show side effects, said J. Michael McFarland, DVM, Dipl. ABVP, the group director of Companion Animal Veterinary Operations at Zoetis. "Veterinarians can now offer six months of uninterrupted heartworm protection to all healthy dogs ages 6 months and older, and provide greater peace of mind to their owners,” Dr. McFarland said. Working with the U.S. Food and Drug Administration’s Center for Veterinary Medicine, Florham Park, N.J.-based Zoetis succeeded in making two other changes: Injections may be done by a veterinary technician or assistant who completes a Web-based training program. A client consent signature is no longer required, a step McFarland termed "unnecessarily frightening for a pet owner.” "Although significant restrictions have been lifted, Zoetis remains committed to education on the proper use of ProHeart 6 and will continue to uphold the guidelines set forth by the FDA to help assure that veterinarians and, through them, pet owners are aware of the benefits and risks of this product,” McFarland said. A new client information sheet explains the risks. Some dogs show mild swelling or itching at the injection site, and pet owners are advised to watch the animal for potential drug toxicity and allergic reactions such as anaphylaxis. The ProHeart 6 safety review was based on adverse event reports collected from June 1, 2008, to December 31, 2012—a period when 2.7 million doses were sold in the United States, McFarland said. ProHeart 6’s six-month efficacy benefits both pets and veterinarians, Zoetis stated. First, a dog remains current with its heartworm medication for a half year, and secondly, the need for another injection brings the dog to the veterinary clinic at least twice a year, presenting the opportunity for wellness checks and other services. A 2009 study conducted by the American Animal Hospital Association found that only 51 percent of owners remained current on their pets’ heartworm medication. Untreated heartworm disease can be fatal.
