A Guide to Canine Heartworm Treatments

Seeking early heartworm treatments for your dog can make the difference between life and death. Heartworm is a parasitic disease which primarily affects the heart and lungs of the dog. It is transferred through a mosquito bite, where larvae of the worm are deposited in the dog's bloodstream. These larvae circulate in the body for 3 months, after which they reach the heart where they attain adulthood.

If there is a large buildup of adult worms, severe damage can occur to the heart, lungs, kidneys and liver. To add to the seriousness of the disease, there is danger of it not getting diagnosed in the early stages. Dogs can live comfortably with a few heartworms in their system. The symptoms show up only after the number of worms has reached dangerous proportions.

Symptoms of Canine Heartworm Disease

  • Laboured breathing
  • Listlessness
  • Lethargy
  • Weight loss
  • Cough
  • Constant state of exhaustion
  • Fluid accumulation
  • Abnormal lung and heart sounds


  • Destroying larvae. Eliminating the immature worms is the first step in treatment. The larvae, also called microfilariae, can be killed within a couple of weeks using macrocyclic lactone drugs containing active heartworm prevention elements.
  • Adult Heartworm Treatment. Eradicating adult worms requires the use of a drug called melarsomine. Doses of this drug are injected in the lower back muscles of the dog.
  • Monitoring. Your dog will be kept under observation in each of the treatment stages until he is considered to be stable and is not reacting unfavourably to the treatment.
  • No Exercise. Once your dog is released from the hospital you will have to make sure he gets no exercise. This is a critical part of his treatment. Exercise will increase the blood circulation, which will in turn increase the chances of developing a block in the arteries due to floating dead worms.
  • Follow Up treatment. There is a high chance that after the treatment your dog may again be carrying microfilariae. After 30 days of the completion of the first round of treatment, your dog will have to be examined again for the larvae. An injection will be administered and he will be observed for a day.
  • Next Action. Your dog will need to undergo regular fortnightly checkups to ensure that there are no larvae in his system. Once that is done, he will be put on preventive medication.

Side Effects

  • Adult heartworm removal is a serious process. The risk to your dog's circulatory system is high, as dead worms are freely moving about in his bloodstream. These can get stuck in the arteries and cause severe problems.
  • Most medicines prescribed for heartworm treatment are a form of arsenic. These are called adulticides. Due to their ingredients, your dog will need to be supervised and monitored for weeks after the treatment. This is to ensure that he does not display any side effects.
  • Inflammation may occur in your dog as a result of the destruction of the worms.
  • The initial injections can cause painful abscesses on your dog, which will need to be treated.
  • The success rate for most dogs infected with heartworm is high. Keeping your dog healthy, providing a proper diet and minimizing exposure to mosquitoes are simple but effective methods of preventing this disease altogether.