Maybe you’ve heard about the law­suit being brought against Mer­ial, the man­u­fac­tur­ers of Heart­gard®? Heart­gard is a heart­worm pre­ven­tive and the law­suit against Mer­ial is by a for­mer employee who claims Mer­ial is cov­er­ing up the low­ered effec­tive­ness of the product.

Start­ing in 2006, Mer­ial was issued warn­ing let­ters by the FDA for mak­ing over­stated claims in its adver­tise­ments, both for claim­ing 100% heart­worm pre­ven­tion effec­tive­ness and for con­trol­ling and treat­ing zoonotic dis­eases.

Iver­mectin is the pri­mary active ingre­di­ent in Heart­gard, and this seems to be the drug heart­worms are devel­op­ing a resis­tance to. Resis­tance which could be as high as a 20% fail­ure rate, accord­ing to inter­nal stud­ies done by Mer­ial, alleges the suing employee. (Two other major brands of heart­worm pre­ven­ta­tives use dif­fer­ent active ingre­di­ents. Inter­cep­tor® and Sen­tinel® by Nor­var­tis uses milbe­mycin oxime. Rev­o­lu­tion® by Pfizer uses selamectin.)

While this is all inter­est­ing, what about your dog? If you’ve been a Heart­gard user, what should you do?

Here is a thought­ful answer by Dr. Watts, a vet writer for the StarExponent.com. (His obser­va­tion that not con­sis­tently using heart­worm pre­ven­ta­tive, of any brand, leads to infec­tion is worth not­ing.)
StarExponent.com — Lifestyles — Should I con­sider chang­ing my dog’s Heart­gard prescription?

More news and details, includ­ing a video inter­view with the suing ex-employee.

For infor­ma­tion more about heart­worms and how to pre­vent them in your pets, visit the Amer­i­can Heart­worm Soci­ety.

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