Ivermectin

Chemical group:      Avermectin, (Macrocyclic Lactone)

Trade names:          Heartgard 30, Heartgard Plus*,  Iverheart Plus,  Heartgard for Cats, Ivomec, etc.

Mode of action:    Binds to glutamate gated chloride channels in the parasites’ nervous system, causing them to open.

Pharmacokinetics:    Rapidly absorbed from the gut, less rapidly from a subcutaneous site. Leaves the body in the feces as ivermectin. Half life in dogs is about 24 to 36 hours.

Dose:    For heartworm prevention:

               Dogs: 0.006 mg/kg (PO), given monthly,  in puppies 6 weeks of age and older. Higher doses not recommended for puppies.

                Cats: 0.024 mg/kg (PO) given monthly.

For other nematodes and for mites: 0.2 to 0.4 mg/kg (PO [SQ in cats]), repeat as needed.

Pigs:  10mg /75 lb body wt.

Toxicity:    In collies, Australian sheepdogs and some collie mixes: toxic signs (lethargy, ataxia, coma) appear above 0.1 mg/kg.  In other dogs, toxic signs are seen at doses at and above 0.8 mg/kg. (Cats probably about the same as dogs). Subcutaneous administration of horse, pig and cattle preparations to dogs or cats may cause local problems due to the vehicle.

Parasite Targets:    Heartworm L4, most nematodes (except adult heartworms²), and mites.

1.  Heartgard Plus also contains Pyrantel Pamoate

2.  Prolonged monthly use may shorten the life span of the adult heartworm.

© University of Pennsylvania  2004

Comments or Questions please contact:  Dr. Nolan at: