Injectable heartworm preventative- aka Proheart is moxidectin.
Advantage multi is moxidectin plus imidacloprid(flea preventative)
From the WSU MDR1 website problems drugs:
Selamectin, milbemycin, and moxidectin (antaparasitic agents). Similar to ivermectin, these drugs are safe in dogs with the mutation if used for heartworm prevention at the manufacturer's recommended dose. Higher doses (generally 10-20 times higher than the heartworm prevention dose) have been documented to cause neurological toxicity in dogs with the MDR1 mutation.
This is same for Ivermectin.
Ivermectin (antiparasitic agent). While the dose of ivermectin used to prevent heartworm infection is SAFE in dogs with the mutation (6 micrograms per kilogram), higher doses, such as those used for treating mange (300-600 micrograms per kilogram) will cause neurological toxicity in dogs that are homozygous for the MDR1 mutation (mutant/mutant) and can cause toxicity in dogs that are heterozygous for the mutation (mutant/normal).
See the full list here:
http://www.vetmed.wsu.edu/depts-vcpl/drugs.aspx
So if you are using proper package low dose preventative of any heartworm drug, it is considered safe in MDR1 mutant/normal or mutant/mutant even ivermectin. If you are formulating your own preventative using cattle or swine products there is a great chance of overdose and this is when any of the above products are problematic. Of course ivermectin usage at high doses of mange and other parasites should be avoided. So go with whatever product you feel comfortable with, it doesn't matter at low doses.
The whole annual injectable moxidectin over a 1 month topical application makes no sense to me. If I was worried about a product why would I inject enough to release over a year and have no way to get rid of it?
