Milbemycinoxim

Milbemycin oxime is an antiparasitic substance used for the treatment and prevention of parasitic infections in animals. It is primarily used against endoparasites like nematodes and ectoparasites like mites. Read more

Milbemycin oxime is an antiparasitic substance used for the treatment and prevention of parasitic infections in animals. It is primarily used against endoparasites like nematodes and ectoparasites like mites.

Essential insights

• Activation of glutamate-gated ion channels: Milbemycin oxime works by activating glutamate-gated chloride channels in the nervous system of parasites. This leads to increased chloride ion influx, causing paralysis and death of the parasite.
• Selective toxicity: The substance is selectively toxic to parasites, as glutamate-gated chloride channels are unique to them. Host animal cells are minimally affected, ensuring safety for the animal.

Breed-specific drug sensitivity

Australian Shepherds, Border Collies, Collies, Old English Sheepdogs, Shetland Sheepdogs, and other related breeds exhibit a breed-specific sensitivity to milbemycinoxim.

High doses of milbemycinoxim can lead to severe neurological symptoms in these breeds, including tremors, ataxia, coma, and, in some cases, death. This reaction is associated with a genetic mutation in the MDR1 gene, which compromises the integrity of the blood-brain barrier and results in increased drug accumulation in the central nervous system.

Other potentially affected breeds include Whippets, Miniature Schnauzers, Chesapeake Bay Retrievers, Boxers, and additional herding breeds such as Belgian Tervurens and Swedish Vallhunds.

In general, milbemycinoxim-containing products are considered safe for dogs with the MDR1 gene mutation, provided the recommended dosage is followed. Refer to the product’s SPC for specific guidance.