Major Uses

Milbemycin is a macrolide antiparasitic that is used to prevent heartworm infections and control hookworms. It may also be effective against adult hookworms, adult roundworms, and whipworms. It is effective at preventing larval infection of dirofilaria immitis in cats. It can also be used to treat generalized demodicosis in dogs.

Common Precautions

Milbemycin should not be taken by animals suffering from a high number of circulating microfilaria, as they can develop a transient, shock-like syndrome. Animals susceptible to the ABCB1 genetic mutation should take reduced doses. The drug should also not be used in puppies younger than 4 weeks of age or smaller than 2 lbs. Kittens less than 6 weeks old or weighing less than 1.5 lbs. should not take milbemycin.

Milbemycin has very few negative symptoms. Dogs susceptible to the ABCB1 mutation can experience CNS toxicity. Puppies may experience ataxia and trembling.

Milbemycin should not be used in animals with a known allergy or hypersensitivity to the drug. A veterinarian should be contacted immediately if an overdose is suspected. Possible symptoms of an overdose include mydriasis, lethargy, hypersalivation, pyrexia, ataxia, seizures, coma, and death.


Milbemycin should be kept at room temperature in a childproof container. It should be kept away from light and out of reach from children and pets.


The minimum dose of milbemycin used for controlling various worm-based infections in dogs is between .05-.99 mg/kg once a month. For microfilaricide chemotherapy, a typical dose in dogs is .5 mg/kg. For treating generalized demodicosis in dogs, a dose of 1 mg/kg a day should be given, and should be increased to 2 mg/kg a day after 30 days if no improvement has been noted. For treatment of cheyletiellosis, scabies, and chronic rhinitis in dogs, a typical dose is between 1-2 mg/kg every 7-10 days for up to 3 doses. For preventing heartworm and treating adult hookworm and adult roundworm in cats, a typical dose is 2 mg/kg once monthly. If a dose is forgotten, it should be given immediately unless it is almost time for the next scheduled dose. In this case, the scheduled dose should be given and the regular administration schedule should resume. Two doses should not be administered at the same time.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.