Ivermectin (Ivomec®, Heartgard®) for Dogs and Cats

Overview of Ivermectin (Ivomec®, Heartgard®) for Dogs and Cats

• Ivermectin, also known as Ivomec® or Heartgard®, is used to control skin parasites, gastrointestinal parasites, and parasites within the bloodstream in dogs and cats.
• Parasitic diseases are common in animals. Parasites can affect the skin, ears, stomach, and intestines, and the internal organs including the heart, lungs, and liver. Several drugs have been developed to kill or prevent parasites such as fleas, ticks, mites, and worms. Ivermectin and related drugs are among the most effective of these.
• Ivermectin is a parasite control drug. It causes neurologic damage to the parasite, resulting in paralysis and death.
• It has been used to prevent parasite infections, as with heartworm prevention, and to treat infections, as with ear mites.
• Ivermectin is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.

Brand Names and Other Names of Ivermectin

• This drug is registered for use in animals only.
• Human formulations: None
• Veterinary formulations: Ivomec® (Merial), Zimectrin® (Farnam), Eqvalan® (Merial), Heartgard® (Merial), Iverhart® (Virbac), and various generic preparations

Uses of Ivermectin for Dogs and Cats

• Ivermectin prevents the development of heartworm disease in dogs and cats.
• Ivermectin can be used in an extra-label manner to kill microfilaria (microscopic offspring) in heartworm infected dogs.
• Ivermectin is not effective against tapeworms and liver flukes.

Precautions and Side Effects

• While generally safe and effective when prescribed by a veterinarian, ivermectin can cause side effects in some animals.
• Ivermectin should not be used in animals with known hypersensitivity or allergy to the drug.
• It should be used with caution in collie breeds or collie mixed breeds due to potential toxic effects. This is particularly true when using higher doses.
• Ivermectin should not be used in dogs that are positive for heartworm disease except under strict supervision of a veterinarian.
• Prior to starting a heartworm prevention containing ivermectin, the dog should be tested for heartworms.
• Ivermectin generally should be avoided in dogs less than 6 weeks of age.
• It is relatively safe, but overdoses can occur if massive amounts are given or if the drug is given to heartworm positive dogs.
• Signs of overdose, including stumbling, tremors, blindness, disorientation, or weakness, generally occur within 12 hours of overdose. In heartworm positive dogs, supportive treatment for shock may be required.
• Ivermectin should be used with caution at high doses when used with Comfortis™, a drug that treats or prevents flea infestations.

How Ivermectin Is Supplied

• Ivermectin is available in 10 mg/ml and 2.7 mg/ml injectable form; 0.153 percent and 1.87 percent paste form; 10 mg/ml liquid oral form and 68 mcg, 136 mcg, and 272 mcg tablets.
• Heartgard Plus® and Iverhart® are available in various concentrations of ivermectin combined with pyrantel pamoate.

Dosing Information of Ivermectin for Dogs and Cats

• Medication should never be administered without first consulting your veterinarian. If you’re concerned about costs related to medication, pet insurance may be able to help. Click here to learn more.
• The dose for ivermectin varies from species to species and also depends on the intent of treatment. General dosing guidelines follow.
• For dogs: Dose is 0.0015 to 0.003 mg per pound (0.003 to 0.006 mg/kg) once a month for heartworm prevention; 0.15 mg per pound (0.3 mg/kg) once, then repeat in 14 days for skin parasites; and 0.1 mg per pound (0.2 mg/kg) once for gastrointestinal parasites.
• For cats: Dose is 0.012 mg per pound (0.024 mg/kg) once monthly for heartworm prevention.
• The duration of administration depends on the condition being treated, response to the medication, and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse and the development of resistance.