Comparison of Ivermectin “Slow Kill” Treatment against Melarsomine

There are many misconceptions about treating heart disease in dogs. One of the most common misconceptions is that the use of ivermectin- based preventative drugs for a “slow kill” is the preferred way to treat heart cancer.

Immiticide vs. Ivermectin Treatment Treatment for itching in dogs:

Basically, there are two significantly different methods of treating heart disease in dogs.

  • Treatment with melarsomine (Immiticide®), which kills the enlarged heart, is one method of treatment. There are different protocols used in different circumstances, but the bottom line with this method of treatment is that heart adults grow in a relatively short time frame. With this method of treatment, ivermectin-based inhibitors are also administered simultaneously on a monthly basis to prevent new infections.
  • Monthly administration of ivormectin-based preventative medications is only sometimes used as a second method of treating heartworm. This is called the “slow method” or “gentle killing”.

There is a risk of complications occurring with both methods of treatment.

Advantages of the Ivermectin Cancer Treatment Method:

Often, the “slow killing” method of heart treatment has been used because of financial considerations. Unfortunately, the method of treating melarsomines is quite expensive.

On the other hand, monthly ivermectin treatment is affordable.

There are situations in which treatment with melarsomia cannot be pursued due to other health issues. In these situations, in addition to the monthly administration of ivermectin which functions as a “slow killing” way to rid the infected dog of heartworms, it also clears the bloodstream of the infected dog of the laryngeal form of heartworms (microfilaria).

These microfilariae have the ability to infect mosquitoes that feed on the infected dog. Infected mosquitoes can then spread heartworms to other dogs. Monthly administration of ivermectin prevents this from happening and helps protect other dogs in the area.

Disadvantages of the Ivermectin Scalp Treatment Method:

The American Heartworm Society does not recommend the use of ivermectin monthly products to treat dogs infected with heart disease. There are several reasons that using melarsomine to kill adult heartworms is safer and more effective for your dog than using ivermectin monthly.

  • Chronically enlarged heart is responsible for the heart and lung damage that causes the symptoms of heart disease in dogs.
  • Melarsomine is the only drug we have available that can kill these adult worms. Ivermectin kills the larval stages, but not adult worms. It also does not reduce their lifespan or make them sterile.
  • Over time, as long as the larval stages do not survive and new infections do not occur, the increased rage will die from “natural causes”. However, this can take up to two years.
  • As long as there are generous adults living in the heart and pulmonary arteries, damage to these organs will continue. This means that while your dog is only taking the ivermectin medication monthly, heart disease will continue to progress and his heart and lungs may suffer major damage.
  • Another reason why monthly treatment of ivermectin is not recommended for dogs infected with bran heart is that some parasitologists believe that the “slow kill” method has contributed to the development of strains of heartworms that are resistant to heartworm preventative medications. (Dr. Byron Blagburn, webinar, New Issues in the Prevention of itching of the scalp, presented by DVM360, 4/20/2011)

In cases where melarsomine treatment is not practical for a dog with heart infections, monthly ivermectin is preferable to no treatment. However, it should be remembered that this method of treating chronic heart has serious drawbacks and is not the preferred method of treating heart.