Milbemycin oxime

The Uses of Milbemycin oxime

Milbemycin oxime is a semi-synthetic macrocyclic lactone prepared by the oxidation and oximation of a mixture of two natural products, milbemycin A3 and A4 (in ~30:70 ratio). Milbemycin oxime is used therapeutically for the prevention of intestinal parasites in dogs. Like the other milbemycin/avermectins, it was developed for intestinal parasite control in animals and acts by opening glutamate sensitive chloride channels in neurons of invertebrates leading to paralysis by hyperpolarisation of these cells and signal transfer blocking.

The Uses of Milbemycin oxime

controls intestinal parasites in animals

What are the applications of Application

Milbemycin oxime is a macrocyclic lactone that acts by opening glutamate sensitive chloride channels

Clinical Use

Milbemycin oxime (Milbemycin) is available as an oral chewable tablet (2.3–27 mg) for heartworm prevention in dogs and cats, as well as a 0.1% otic solution for treating ear mites. It is not available in a more concentrated dosage form, so overdoses are relatively rare[1].

Toxicology

The therapeutic dosages of Milbemycin oxime (milbemycin) for heartworm prevention are 0.5 mg/kg in dogs and 2 mg/kg in cats. Mild clinical signs of ataxia, hypersalivation, mydriasis, and lethargy have been documented in ivermectin-sensitive dogs dosed at 5 to 10 mg/kg. In a separate report, two ABCB1-defective dogs developed mild signs (ataxia) after being dosed repeatedly with milbemycin for demodicosis; one dog received 0.8 mg/kg 2 days in a row, and the other dog received 1.5 mg/kg daily for 13 days before developing signs. Mild clinical signs have been reported to develop in normal dogs at 10 to 20 mg/kg and in cats and dogs with suspected ABCB1 gene deletions greater than 5 to 10 mg/kg. The most common clinical signs reported include ataxia, tremors, lethargy, vomiting, mydriasis, disorientation, and hypersalivation[1].

Veterinary Drugs and Treatments

Milbemycin tablets are labeled as a once-a-month heartworm preventative (Dirofilaria immitis) and for hookworm control (Ancylostoma caninum). It has activity against a variety of other parasites, including adult hookworms (A. caninum), adult roundworms (T. canis, T. leonina) and whipworms (Trichuris vulpis). In cats, milbemycin has been used successfully to prevent larval infection of Dirofilaria immitis.
Milbemycin, like ivermectin can be used for treatment of generalized demodicosis in dogs, but treatment can be significantly more expensive. It is likely safer to use in breeds susceptible to mdr1 genetic mutation (Collies, Shelties, Australian shepherds, etc.) at the doses used for this indication, but neuro toxicity is possible. Older dogs, those that have had a long duration of disease prior to treatment, and dogs with pododemodicosis appear have a lower success rate with milbemycin treatment.

References

[1] DVM, Valentina M. Merola, Paul A. Eubig DVM MS and MS. “Toxicology of Avermectins and Milbemycins (Macrocylic Lactones) and the Role of P-Glycoprotein in Dogs and Cats.” Veterinary Clinics of North America-Small Animal Practice 42 2 (2012): Pages 313-333.