Bayer and Merck Put Pets at Risk

Bayer & Merck Anti-Flea & Tick Products for Pets: Animal Health & Environmental Risks

By Michael W. Fox, BVetMed, PhD ,DSc, MRCVS

children playing with dog in the parkBayer’s dog and cat “Seresto” anti-flea and tick collars contain a nicotine chemical (imidacloprid) that can cause seizures, thyroid gland damage, mutations, abortions and birth defects, (and is a class of widely used agricultural chemicals implicated in the catastrophic demise of honey bees, banned by the European Commission in 2013 for 2 years in Europe); and a pyrethrin chemical (flumethrin) that can cause nausea, vomiting and seizures among other harmful side effects. There is also the concern of children and adults petting animals with these chemicals seeping over the animals’ skin, and of the animals grooming themselves and each other.

Now Bayer has gone bug-wild with a plethora of new related anti-bug products. The products within the “Bayer Pest Solution Center” are organized into three categories: Prevent, Treat, Control. The prevention section comprises three Bayer lines – K9 Advantix® II, Seresto® and Advantage® II – while the treatment and control sections feature Bayer’s new products. Bayer is also supporting pet specialty retailers with training modules and toolkits for employees to enable them to help their customers. These new products containing similar ingredients include – Advantage® Treatment Spray for dogs, Advantage® Treatment Spray for cats, Advantage® Treatment Shampoo for dogs, and Advantage® Treatment Shampoo for cats and an array of Advantage Household Spot & Crevice Spray, Advantage Carpet & Upholstery Spot Spray, and Advantage Household Fogger to kill indicated pests in the home, and Advantage Yard & Premise Spray that kills pests in the yard and around the house.

Soak it up folks and join Bayer’s environmental bug buggery, or as we say in the North of England, “Bugger off”. The drug company is banking on a combination of public ignorance, trust and fear of fleas and other noxious insects, safer controls for which are documented on my website .

It should be noted that there is no guarantee of animals not developing allergic reactions to flea and other insect bites, or from contracting an insect-born disease, the company stating: “advantix® provides repellent (anti-feeding) activity against ticks, sand flies and mosquitoes, thus preventing the repelled parasites from taking a blood meal and thus reducing the risk of disease transmission (e.g. Lyme borreliosis, babesiosis, anaplasmosis, ehrlichiosis, rickettsiosis, leishmaniosis). However, there may be an attachment of single ticks or bites by single sand flies or mosquitoes. For this reason, a transmission of infectious diseases by these parasites cannot be completely excluded if conditions are unfavourable….. Following topical application in dogs, the solution rapidly distributes over the body surface of the animal. Both active substances remain detectable on the skin and hair of the treated animal for 4 weeks…. Acute dermal studies in the rat and target animal, overdose and serum kinetic studies have established that systemic absorption of both active substances after application on intact skin is low, transient and not relevant for the clinical efficacy”. Why no long-term studies?

The British government authority that approves drugs for veterinary use in the U.K. has advised that Merck’s Bravecto chewable tablets of all sizes must have a label warning: “Use with caution in dogs with pre-existing epilepsy.” (The Veterinary Record, Sept. 2017, p.340).The warning from the manufacturer posted in the U.S. does not yet include this, and reads: “The most frequently reported adverse reactions include vomiting or diarrhea. Other side effects that may be seen include decreased appetite, lethargy, increased thirst, and flatulance.(sic). Consult your veterinarian if you notice any of the above side effects. Bravecto is for use only in dogs”. Another entry states: “The most common adverse reactions recorded in clinical trials were vomiting, decreased appetite, diarrhea, lethargy, polydipsia, and flatulence. Bravecto has not been shown to be effective for 12-weeks’ duration in puppies less than 6 months of age. Bravecto is not effective against lone star ticks beyond 8 weeks of dosing”.

According to “ Fluralaner (the active ingredient of BRAVECTO) and other isoxazolines are non-competitive GABA (gamma-aminobutyric acid) receptor antagonists that bind to chloride channels in nerve and muscle cells, which blocks the transmission of neuronal signals. Affected parasites are paralyzed and die. This mechanism exists not only in insects but also in mammals and other vertebrates. However the binding affinity of fluralaner to GABA receptors of invertebrates is much higher than to GABA receptors in vertebrates. For this reason it is significantly less toxic to mammals than to insects and other pests”.

“Less toxic” is quite different from not toxic. Long-term toxicity has not been evaluated, especially chronic neurological and carcinogenic effects. Time to stop this foolishness and help bring back the insects to our communities and stop using pesticides in and around our homes and communities and putting these poisons on our pets, neonicotinoids as in Seresto in particular, and even on most of the food we eat. It is probable that Bravecto and Seresto in dogs’ feces and urine continues to be active, making treated dogs insect killers with potentially serious adverse environmental consequences.

Eucalyptus extract and leaves are alternative pest repelents for better healthThe tried and true knowledge and use of herbal products by indigenous peoples have developed over millennia to safely and effectively repel, control and kill noxious insects, including Eucalyptus, Peppermint and Tea Tree oils, India’s Neem oil, Peru’s Quassia, are my choice. (Visit to see how one of a few companies are now marketing these kinds of natural products for effective and safe use for cats and dogs) Furthermore, these products cannot be patented and are far less costly than those of the multinational drug companies such as Bayer that also sell to the chemical-toxic agribusiness industry. To suggest that people should use their “Advantage” product on their yards and properties totally disregards the impact on beneficial insects and the birds, reptiles, bats and other wildlife who consume them.

Government legislators and municipal authorities should move to ban the sale of these kinds of products in stores across their jurisdictions. If we chose to be deaf to reason and common sense, then we will not notice or care about the silencing of this living world. Many already notice the absence of the butterflies in their yards and gardens and of once a myriad kinds of insects around night lights everywhere. But will they understand that when the diversity of beneficial insects and insectivores is gone they will be more vulnerable to ever more insect-borne diseases? This is in part because the most “noxious” insects—those species in part aided in their proliferation because of our ecological interferences—develop resistance to our armament of chemical warfare against them. This causes collateral damage to other harmless and beneficial species. Great economic losses for farmers ( already being experienced by almond and citrus crop growers), and famines will come when there are no bees and other pollinators for the plants, and no plant-pest killing parasitic wasps who indirectly sustain us, our economy and those diminishing other species who can barely endure the planetary infestation and mindless onslaught of our species?

I never imagined that I would come live in a world where multinational corporations would exploit not only nature’s resources for pure profit regardless of the social and ecological costs and harmful consequences but garner the findings of the biological sciences to produce crops that manufacture their own insecticides and have resistance to herbicides, all products they sell along with their patented, genetically engineered seeds.. But all to what end? The profit motive and the adversarial and bio-fascist attitude of corporations and of segments of society toward other living beings and the natural world will be the ultimate undoing, the nemesis of this bioindustrial epoch in human evolution, leading to the extinction of this mode of being and state of mind, if not of Homo sapiens itself.

The author is a veterinarian and bioethicicst with doctoral degrees in medicine and ethology/animal behavior from the University of London, England. He writes the syndicated newspaper column with UniversalUclick, “Animal Doctor”. Website