Ivermectin/heartworms

[MargePiwowarski <MPiwowarski@compuserve.com>]

Shannon,

There *is* a protocol for using ivermectin to kill adult heartworms.  It is
much less toxic to the dog than arsenic, but all the other hazards remain
the same, ie a dead worm will embolize to the lungs and if you kill too
many or don't keep the dog quiet; the dog can get just as dead from
pulmonary emboli as from heartworms and it is a more sudden death.

You are correct that in the lower doses, only microfilaria are killed. 
Unless the dog has been on preventative from birth, he needs a heartworm
test before starting any treatment/preventative at all.  

Following adult heartworm treatment with ivermectin, one won't see a
negative ELISA for at least three months, takes that long for the
antibodies to depart the dog following completion of sucessful treatment. 
The lowered toxicity from the drug itself have enabled us (with veterinary
direction) to treat rescue dogs who couldn't have survived the old arsenic
routine.  We have done *old* dogs,  already in congestive heart failure
from heartworms and haven't lost one to date.  We have taken as long as 3-4
months to complete the adult "kill" with several weeks of continuing to
keep the dog quiet after the final dose.  We treated our first positive
rescue dogs, um, 7-8 years ago; are there still people out there using
arsenic?

Marge