Since treating Symptoms of heartworms in dogs is extremely risky and hard on the dog, the preferred route is taking preventative measures. Conventional preventive measure is the use of drugs to kill the heartworm larvae (microfilaria) before they mature. The most common preventative drugs for heartworm are ivermectin (Heartgard®), milbemycin (Interceptor®) and selamectin (Revolution®). Compared to other medications, these drugs are generally safe and effective as the dose needed to prevent heartworm infection and disease is very tiny, approximately 1/30 of that necessary to treat other parasitic diseases. However, the drugs can cause side effects in some dogs. Side effects associated with ivermectin include depression, balance problems, and blindness, although these are uncommon at the low doses used in heartworm preventatives. However, ivermectin should be used with caution in collies and related breeds such as Old English Sheepdodgs and Australian Shepherds, who are more sensitive to the neurological effects of the drug. Milbemycin, the most common alternative drug for collie breeds, can cause depression, lethargy, vomiting, appetite loss, diarrhea, convulsions, weakness and excessive drooling. Selamectin side-effects include diarrhea, vomiting, muscle tremors, appetite loss, lethargy, drooling, and rapid breathing.
Treating heartworm in dogs is very involved and almost always requires hospitalization. The treatment can be very dangerous as well because the drugs used are arsenic-based and are understandably very toxic. Treating heartworm involves the injection of the heartworm drugs into an Symptoms of heartworms in dogsto kill the adult heartworms. However, unlike intestinal worms which can then be eliminated through the digestive system, the dead heartworms have nowhere to go - they die in the heart chamber and the pulmonary arteries and then start to decompose over about 30 days. During the 30 days after the injection, the dog patient has to be kept very quiet to decrease the chances of these tiny pieces of dead worms from going into the deeper arteries of the lungs causing obstruction of the blood vessels, which can sometimes cause immediate death to the dog. Also, the massive die-off of the Symptoms of heartworms in dogs can cause severe inflammation and even respiratory failure. Sadly, not all dogs survive the treatment. If your dog unfortunately requires heartworm treatment, use herbs such as Milk Thistleto minimize toxicity from the medications.