Heartworm med recommendations needed.

[Back40]

My 4 rescues have been on Sentinel and Interceptor but since the Novartis plant is offline, I am looking for other recommendations. My vet suggested Heartguard but I have read about some potential effectiveness problems plus my 4 dogs are mixed breeds so they may have some herding genetics. Thanks!

[Barb04]

My vet has told us to use Iverhart Max until Interceptor is available again.

http://www.iverhart.com/Products/

[Saeleofu]

As far as possible MDR1 (assuming this is the "herding genetics" you are talking about), it's not just ivermectin those dogs are sensitive to, but also selametin (active ingedient in Revolution) and milbemycin oxime (active ingredient in Interceptor and Sentinel). That being said, the amounts in heartworm preventatives are NOT enough to cause problems for a dog with multiple drug sensitivity. I have a collie and he's taken Heartgaard (ivermectin) and Trifexis (milbemycin) with NO problems.

That being said, Trifexis has done collie-specific safety testing and they had no problems with it. It is the same active in gredient as Interceptor, plus flea control (same active ingredient as Comfortis). If you want milbemycin, this is the only option if you can't get Interceptor/Sentinel. Otherwise it's an ivermectin-based drug or something like Revolution or Advantage Multi, and I personally don't trust topical heartworm meds.

[GlassOnion]

Milbemycin-oxime and moxidectin are both safer to use than the avermectins (ivermectin, selamectin, doramectin, eprinomectin) in dogs with MDR1 mutations.

Ivermectin can be safe as long as you use it on-label for the most part, but a milbemycin is preferred. I seem to recall selamectin being OK to use as well, but not preferred.

[sassafras]

Originally Posted by GlassOnion

Milbemycin-oxime and moxidectin are both safer to use than the avermectins (ivermectin, selamectin, doramectin, eprinomectin) in dogs with MDR1 mutations.

Ivermectin can be safe as long as you use it on-label for the most part, but a milbemycin is preferred. I seem to recall selamectin being OK to use as well, but not preferred.

It frustrates me that this belief is still out there. ALL heartworm preventatives are on the MDR1 problem drug list, but at doses used for heartworm preventative ivermectin is perfectly safe for MDR1 mutants. It's at higher doses used for other problems such as demodex that it is a concern.

From the WSU website:

"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)."

"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."

[naturalfeddogs]

What about Advantage Multi? Ask your vet about that one.

[*blackrose]

I've used Heartguard in the past, no problem. (Chloe is an Aussie/Collie mix and had no adverse reaction to it whatsoever.) We just got some Trifexis free through work, so that is what the dogs are on currently. Haven't had a problem with it, either, and I'll likely stick with it since it is also flea control.

[naturalfeddogs]

Advantage Multi gets fleas, heartworm and some others I can't remember which, but about three or four other parasites. Its supposed to be one that has had no failer rates as well I believe.

[GlassOnion]

Originally Posted by sassafras

It frustrates me that this belief is still out there. ALL heartworm preventatives are on the MDR1 problem drug list, but at doses used for heartworm preventative ivermectin is perfectly safe for MDR1 mutants. It's at higher doses used for other problems such as demodex that it is a concern.

From the WSU website:

"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)."

"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."

Even better, then.