Canine Heartworm Preventative: Numbers Tell the Story

Since receiving approval by the Food and Drug Administration in June 2001, ProHeart® 6 (moxidectin) has emerged as the fastest-growing canine heartworm preventative in the United States. This couldn’t have come at a better time considering that heartworm infection rates have remained unchanged over the past 10 years, despite the widespread availability of conventional preventatives.

Unlike monthly pills administered by the dog owner, ProHeart 6 is an injectable six-month preventative that is administered exclusively by the veterinarian. This professional control virtually eliminates the heartworm compliance problems that have traditionally plagued veterinarians and clients.

“The acceptance of ProHeart 6 by both veterinarians and dog owners has exceeded our expectations,” said Craig Wallace, Director of the Companion Animal Division of Fort Dodge Animal Health, which manufactures ProHeart 6. “We knew that ProHeart would challenge the current veterinary protocols in canine heartworm prevention. Yet, we were amazed at how quickly veterinarians were willing to enthusiastically embrace this new approach to protection.”

According to Wallace, in less than 18 months, ProHeart 6 has achieved in excess of a 17 percent share of all heartworm products dispensed through clinics, with some key markets exceeding 20 percent.

“ProHeart 6 has had a dramatic impact on the canine heartworm preventative market,” said Wallace. “We were extremely encouraged with our results. While ProHeart 6 market share has continued to increase each month during 2002, data shows that our major competitors have experienced a steady decline.”

ProHeart 6 contains the active ingredient moxidectin, a new-generation milbemycin molecule, in combination with a unique microsphere technology delivery system. A single-dose injection provides unprecedented sustained-released protection against canine heartworm disease for six continuous months. Wallace attributes much of the success of ProHeart 6 to progressive veterinarians who are adopting this breakthrough approach to heartworm protection.

“Clearly, ProHeart 6 represents the future direction of heartworm protection. It puts the veterinarian in control,” said Wallace. “Unlike the monthly preventatives that dog owners administer themselves, with ProHeart 6, the veterinarian controls the timing, administration, accuracy and efficacy of the preventative dose. Protection is no longer dependent upon owners remembering to give the medication every month.”

Veterinarians cite many reasons for incorporating ProHeart 6 into their practice, but chief among them is the problem they have with clients failing to comply with the monthly administration protocols.

“I started using ProHeart 6 because of compliance issues. Lots of people forget to give the monthly heartworm pill, including myself,” said Doug Wojcik, DVM of Liverpool, New York.

Similar sentiments were expressed by Karen Michalski, DVM of Sterling Heights, Michigan. “With ProHeart 6, my confidence level is much greater, knowing that the pet is receiving the medication. Many clients have switched, especially those who initially resisted putting their pets on heartworm preventative. They appreciate the fact that they don’t have to worry about heartworm prevention anymore,” said Dr. Michalski.

Despite advancements in heartworm prevention over the past decade, client compliance still remains a major issue. A recent released survey by the American Heartworm Society revealed that infection rates over the past 10 years have not changed.

Veterinarians, such as Dr. Theresa Ruth of Grand Island, New York, report that their clients like having the responsibility of heartworm protection removed from their shoulders with ProHeart 6. “Dog owners love the idea that they don’t have to remember a monthly dose anymore. We recommend ProHeart 6 pretty much all the time now. The majority of our clients have switched over,” she said.

“Our clients appreciate the fact that heartworm prevention can be taken care of in the veterinarian’s office, instead of trying to remember the monthly dose. ProHeart 6 relieves the client of one more thing to remember in their busy lives,” said Duane Schnittker, DVM, of Brentwood, California.

For some veterinarians, having their clients bring their dogs into the clinic every six months for the ProHeart 6 injection has given them an opportunity to practice better preventive medicine. “We’re truly excited about the benefits ProHeart 6 brings to our practice. The six-month office visit gives us an opportunity to assess the patient’s other healthcare needs on a regular basis,” explained James Denhart, DVM, of Des Moines, Iowa. “Instead of clients purchasing through non-veterinary channels, like the Internet, we stay in control with ProHeart 6.”

A national industry survey of 2,500 dog owners revealed that more than 80 percent would switch to twice-a-year heartworm protection if it cost no more than their current monthly preventative.

Currently, the average dog is already taken to the veterinarian 1.8 times a year for wellness checkups, grooming, boarding, dental work and other procedures, according to the American Veterinary Medical Association. In fact, veterinary practice management experts recommend twice-a-year office visits for healthier dogs, as well as for more beneficial interaction with dog owners. This emerging trend fits well with the ProHeart 6 protocol.

ProHeart® 6 (moxidectin) has been proven safe and effective in multiple U.S. field trials. Multiple target animal safety studies have been conducted in a wide variety of adult dogs, including collies with known sensitivity to ivermectin. Efficacy and safety studies were conducted by researchers from many leading veterinary schools of medicine in the United States.

Fort Dodge Animal Health has developed a website – – to provide veterinarians with further information and background on ProHeart 6.

ProHeart® 6 (moxidectin) is generally well tolerated. Use with caution in sick, debilitated or underweight animals. A small percentage of dogs showed mild, transient swelling or itching at the injection site. While rare, digestive, neurological or hypersensitivity reactions may occur. Read the package insert for more information. To obtain additional information, including a copy of the product labeling, veterinarians can visit or call 1-800-533-8536.

To order ProHeart® 6 (moxidectin), veterinarians should contact their Fort Dodge representative or call Fort Dodge Animal Health at 1-800-685-5656.

Fort Dodge Animal Health, a division of Wyeth (NYSE:WYE), is a leading manufacturer and distributor of prescription and over-the-counter animal health care products for the livestock, companion animal, equine, swine and poultry industries in North America and international markets. Key Products include CYDECTIN® Pour-On, QUEST® Gel, EtoGesic® Tablets, ProHeart® Injection, Fel-O-Vax® FIV and Innovator™ equine vaccines including West Nile virus. The company is headquartered in Overland Park, Kansas.


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