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Merck Animal Health has announced a new flea +/- tick drug called Activyl.
Activyl is a topical flea prevention product like Advantage or Frontline, but with some extra super-fancy features.
The active ingredient in Activyl is a new chemical called indoxacarb (commonly used in ant traps, hence the snappy title to this blog post). Indoxacarb is classified as a non-organophoshorous oxadiazine insecticide.
What’s with the name Activyl anyway? Merck wants you to know that indoxacarb doesn’t kill bugs until it gets “bioactivated” – once the insect eats the indoxacarb, enzymes inside the insect convert the indoxacarb into this stuff called IN-JT333/DCJW, that disrupts insect nerve pathways causing rapid paralysis and insect death.
Indoxacarb is relatively harmless in people and pets, because mammals are lousy at converting indoxacarb into IN-JT333/DCJW.
Activyl / indoxacarb also possesses both larvicidal and ovicidal activity, meaning it treats all life stages of the flea and breaks the entire flea life cycle, helping with environmental flea control. No additional insect growth regulators are required.
Is Activyl toxic to dogs or cats?
This is always my biggest concern with a new drug on the market, and I’m pleased to report Activyl is pretty darn NON-toxic.
According to the EPA, Indoxacarb has moderate to low acute and chronic toxicity and does not cause mutagenic, carcinogenic, developmental, or reproductive effects in any mammal species tested. The EPA also noticed No Observable Adverse Effects of indoxacarb even at 5.0mg/kg orally for 90 days. (hemolytic anemia was noted at 19mg/kg). (European studies report indoxacarb’s No Observable Adverse Effects dose in male dogs is lower, 2.0mg/kg)
Skin irritation appears to be low, and Activyl supposedly dries faster on skin than does Advantage or Frontline, meaning less annoying grease on your pet. Hooray!
Activyl by itself (without the “plus”) has ZERO acaricidal activity, ie: does not kill ticks. That’s why Merck had to add our old friend permethrin to make the “tick plus” in Activyl Tick Plus. (keep away from cats!!!!)
Regarding expected side effects: Again in the European study, in less than 10% of dogs scratching was observed, and very few dogs showed signs of hair loss and itching and one dog showed a cutaneous lesion. In less than 5% of cats adverse effects were observed, consisting of excitation, anorexia, vomiting an excessive salivation (presumably because the cat licked off the drug and it tastes yucky). A local reaction (hair loss) was observed in another cat. Signs resolved with or without therapy.
Shampooing, water immersion or sunlight do not appear to result in a reduced efficacy of Activyl, when flea counts were made after one week.
I found one report of a human who attempted to commit suicide by ingesting indoxacarb (he failed) and toxicity caused methemoglobinemia treated with methylene blue. Presumably if a dog or cat were to ingest enough of this stuff, similar anemia / methemoglobinemia might maybe possibly happen, but that seems unlikely.
Even the anonymous drug-rep grumpsters at CafePharma have nothing negative to say about Activyl, except that it’s mostly just Advantage / K9 Advantix but with a different (and more effective) molecule instead of the imidocloprid found in Advantage.
SO HERE’S MY BOTTOM LINE ABOUT ACTIVYL:
Activyl contains a new chemical indoxacarb, so cases of flea resistance to Frontline or Advantage will do well with this new drug.
Activyl Tick Plus sadly contains the same cat-toxic permethrin that’s present in K9 Advantix, and Vectra 3D. DO NOT APPLY ACTIVYL TICK PLUS TO A CAT, or let your cat groom your dog once Activyl Tick Plus has thoroughly dried on the dog.
Will I switch from my favorite Vectra 3D to Activyl? Probably depends which is cheaper. LOL!
In all seriousness though, I like this stuff, at least on paper.
UPDATE 7-26-12: We got some samples of Activyl today (not Activyl Tick Plus) and although it’s marketed as odorless, there was a distinct cheap-vodka alcohol scent when it was first applied, then as the alcohol (quickly) evaporated, it left a mildly shiny (but not greasy) residue and kind of unpleasant, well, pesticide odor.
Please remember, flea preventives are only effective if applied monthly for 3 consecutive months to all pets in the house. In Indiana, flea preventives should be used all year round. Please contact our office at 317-721-7387 if you have additional questions.