Question:

Are there any new heartworm treatments?

Answer:

There are reports that the annual number of heartworm positive dogs is about 1,000,000!

Only two drugs have been approved over the last 30 years to treat heartworms in the dog, the most recent one having been introduced over 10 years ago, so unfortunately, there are no new treatments for adult heartworms.

Both of these treatments are potent arsenical compounds with serious side effects. The newer product is safer and more effective than the older product so it is the treatment of choice. The goal is to kill the parasite without killing the pet, but the margin of error is quite slim. Three times the therapeutic dose is the lethal dose.

Cats can be infected with heartworms as well, though there are no safe treatments for cats.

You may know that heartworms are spread to dogs and cats by mosquitoes. The mosquito is considered an intermediate host in the life cycle of the heartworm. Mosquitoes do not inherently harbor heartworms, but feed on a dog that has adult heartworms. In their blood meal, they obtain larval stages of the heartworm called “microfilaria”. After incubating the microfilaria for a short period of time to an infective stage, the mosquito then spreads them while feeding on a new host.

While circulating microfilaria are quite common in dogs with adult heartworms, cats very rarely have them in their peripheral blood therefore, a heartworm positive cat does not pose the risk of being a reservoir of infection to neighboring pets that a positive dog does. This is why we often see pockets of infections in areas where there is a heartworm positive dog and other pets in the neighborhood are unprotected.

Unfortunately mosquito control is not practical in the cat and does not provide enough protection to prevent the spread of heartworm disease in the dog. However, there is no reason for your pet to ever develop a heartworm infection.

While there are a limited number of treatments, there are a number of safe and convenient heartworm preventatives on the market today available in several different forms. Additionally, there are convenient monthly topically applied products. The newest of the topical products, Advantage Multi for Dogs (imidacloprid + moxidectin) Topical Solution and Advantage Multi for Cats (imidacloprid + moxidectin) Topical Solution, not only prevent heartworm disease, but also kill adult fleas, treat flea infestations, as well as treat and control multiple common parasites. Advantage Multi for Cats also treats and controls ear mite infestations.

The Companion Animal Parasite Council (CAPC) makes a general recommendation that heartworm preventative be used year-round, or as directed by your veterinarian. CAPC also recommends that dogs over 4 months of age first have a heartworm blood test before starting a preventative program. I suggest that you visit the CAPC website for their recommendations on all types of parasites at: www.petsandparasites.com.

It’s important to note that all heartworm preventatives are regulated by the Federal Drug Administration and therefore require a prescription from your veterinarian. Always consult your veterinarian for his or her local recommendations, as they may vary depending on the specific part of the country you live in.

Dr. Revoir’s veterinary opinion should only be used as an educational guide and in no way should be substituted for licensed veterinary care. Your veterinarian should be consulted in all health matters involving your pet.

Advantage Multi^® for Dogs (imidacloprid + moxidectin) Topical Solution
CONTRAINDICATIONS: Do not administer the product orally. Do not use this product (containing 2.5% moxidectin) on cats. WARNINGS: For the first thirty (30) minutes after application, ensure that dogs cannot lick the product from application sites on themselves or other treated dogs, and separate treated dogs from one another and from other pets to reduce the risk of accidental ingestion. Ingestion of this product by dogs may cause serious adverse reactions including depression, salivation, dilated pupils, incoordination, panting and generalized muscle tremors. In avermectin sensitive dogs, the signs may be more severe and may include coma and death. HUMAN WARNINGS: Children should not come in contact with the application site for two (2) hours after application. Additional Safety Information

Advantage Multi^® for Cats (imidacloprid + moxidectin) Topical Solution
WARNINGS: Do not use on sick, debilitated, or underweight cats (see ADVERSE REACTIONS). Do not use on cats less than 9 weeks of age or less than 2 lbs. body weight. HUMAN WARNINGS: Children should not come in contact with the application site for 30 minutes after application. PRECAUTION: Avoid oral ingestion. Additional Safety Information