Preventives
While treatment of canine heartworm disease is
usually successful, prevention of the disease is
much safer and more economical. There are a
variety of options for preventing heartworm infection, including daily
and monthly tablets and chewables, monthly topicals and a six-month
injectable product. These products are extremely effective and when
administered properly on a timely schedule,
heartworm infection can be prevented.
Veterinary Online Institute is now recommending year-round prevention, even in seasonal areas.
One reason for this is compliance
– to make sure the medicine has been given properly by the pet
owner. In addition, most monthly heartworm
preventives have activity against intestinal parasites.
Many of these same intestinal parasites that
infect dogs can also infect people, with estimated infections
occurring in three to six million people every
year. So this added benefit of monthly deworming makes great sense.
Before starting a preventive program, all dogs that could possibly be infected with mature heartworms should be tested.
Macrocyclic Lactone (ML)
Macrocyclic lactones are highly effective parasiticides
used in
preventing heartworm infections. Their primary
benefits lie in their safety and ease of administration of once-
monthly doses. Each of the macrocyclic lactones can have additional intestinal parasite or external parasite activity,
which could be the determining factor that a veterinarian uses to recommend a particular product for
a certain region or an individual situation.
Ivermectin
Ivermectin (Heartgard
® & Heartgard
® Plus by Merial,
Iverhart
® Plus & Iverhart MAX™ by
Virbac and Tri-Heart® Plus by Schering-Plough)
was the first in this family of drugs to be
approved for preventing heartworm infection. An infection with larvae as long as two months prior to the initiation of ivermectin
treatment will be blocked from development.
Milbemycin
Milbemycin oxime (Interceptor
® & Sentinel
® by Novartis) has benefits, which are similar to ivermectin.
Selamectin
Selamectin (Revolution
® by Pfizer) is applied topically to prevent heartworm disease.
Moxidectin
Moxidectin (Advantage Multi™ by Bayer) is available in a topical formulation, in combination with
a flea control product, imidacloprid.
Moxidectin is also available as a six-month injectable product for dogs (ProHeart
®6 (moxidectin) Sustained Release Injectable for Dogs, by Fort Dodge Animal Health).