Major Uses

Milbemycin oxime and spinosad is a drug most commonly used to prevent heartworms, kill fleas and prevent infestations, and kill some internal and external parasites. It can also prevent and control adult hookworms, roundworms, and whipworms.

Common Precautions

Milbemycin oxime and spinosad should not be used in animals with epilepsy. It should also not be used in collies or other hunting breeds unless a veterinarian is supervising. Hunting breeds may suffer from side effects such as weakness, fever, staggering, trembling, or dilated pupils. Puppies under the age of 8 weeks, or under 5 pounds should not take milbemycin oxime and spinosad. The safety of milbemycin oxime and spinosad in breeding animals has not fully been tested, so caution should be used.

Some negative side effects associated with milbemycin oxime and spinosad are vomiting, decreased appetite and activity, itching, reddening of the skin, and diarrhea. Signs of an allergic reaction can include facial swelling, scratching, hives, diarrhea, vomiting, shock, seizures, cold limbs, pale gums, or coma.

Milbemycin oxime and spinosad 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, the symptoms of which include tremors, vomiting, salivation, coughing, vocalization, and decreased activity.


Milbemycin oxime and spinosad should be kept at room temperature and stored in a tight, light resistant, childproof container. Steps should be taken to keep the drug away from the reach of children and pets.


Milbemycin oxime and spinosad is given in tablet form with food. It is administered on a strict schedule of one tablet per month. When treating parasitic conditions, the pet should be tested for every 6-7 months in order to determine if medication should continue. Any missed doses should be given as soon as possible. Should it be nearing the time for the next scheduled dose, the missed dose should be skipped and the regular administration schedule should resume. Two doses should never be given 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.