This article is from the Canine Medical Information FAQ, by Cindy Tittle Moore with numerous contributions by others.
_As of 1997, there is a new treatment method for dogs with
heartworm. I have been informed that Immiticide (Melarsomide) is an
intramuscular injectable heartworm treatement that obsoletes
Caparsolate. I do not know how this functions or how it differs in
treatment considerations for the dog. _
Treatment for heartworms is difficult on the dog and prevention
is easy. If your dog tests positive for heartworms and you
decide to treat it, here is what will happen: Your vet will
want to take a blood sample to begin with to check the dog's
liver function. The treatment that kills the adult worms uses a
drug called Caparsalate. This drug is given twice a day for 2
days while the dog is in the hospital. The dog must be kept
quiet (caged) for 4 weeks after the adult worms have been
killed. It takes 7 to 17 days from the time of treatment for
the adult worms to die. Within this time, dead worms will
fragment and travel to the dog's lungs. If dead worms are
numerous, some of the blood vessels to the lungs will become
blocked, and this is inevitable. However, if the dog is kept
quiet and only allowed to move around enough to go outside, the
blockage of pulmonary vessels may remain subclinical. If the
dog is allowed to run around, the heart rate increases and many
dead worm fragments will travel to the lungs at the same time.
This is what you want to avoid. About 4 weeks after Caparsalate
has been given, the dog will be given a high dose of ivermectin
to kill the remaining microfilaria that are circulating.
Although this is a high dose of ivermectin, it is below the
lowest dose known to cause mild, self-limiting toxic side
effects in Collies. Obviously, after being treated, dogs should
be kept on heartworm preventative!
Summary Of Medication
Heartworm preventives include
o Prevents hookworm infestations as well as heartworms.
o Safe for Collies. Monthly.
o Excellent control of hookworms and roundworms as well as
o Has caused seizures in higher doses to Collies. Monthly.
+ Filarbits Plus
o Contraindicated if microfilariae are already present in
o Controls hook, round, and whip worms to some extent. Can
be used in puppies 8 weeks or older. Daily.