Heartworm spreads from mosquitoes through bites to animals like dogs, cats, foxes, wolves, coyotes, other animals and even humans that live near areas with large mosquito populations. Heartworm infection is dangerous; untreated dogs may die and treatment is also risky. Treated dogs experience weeks or months of discomfort while the parasites are killed and expelled from their bodies.



The following medications are only a few medications used in treating and preventing heartworm disease. Before using any medications you should speak with a veterinarian as your dog's life might at stake.

Moxidectin, marketed under the brand name ProHeart, is an injectable parasiticide that is used in treatments for prevention and control of heartworm and intestinal worms. Moxidectin should be administered within one month of the dog exposure and prevents infection for six months after administration. After these months, if the dog reacts well to the drug, it can be administered every six months for continuous protection to the heartworm disease.

The following side effects may occur: anaphylaxis, vomiting, diarrhea (with and without blood), listlessness, weight loss, seizures, and high body temperature. If your dog is already infected with heartworm disease side effects like vomiting, lethargy and bloody diarrhea might occur.

Ivermectin can also be found under the brand names Tri-Heart Plus, Heartgard, Ivomec, Heartgard Plus or Iverhart Max. All these medications contain ivermectin and pyrantel. Iverhart Max contains also praziquantel.

In dogs, Ivermectin is used as a preventive drug for heartworm disease but it is also effective in clearing heartworm larvae in active heartworm infection. Ivermectin can only be obtained from your veterinarian or with a prescription from a veterinarian. You should follow strictly the dosage directions provided by your veterinarian when you administer this drug to your dog. Usually it's prescribed for usage during mosquito season and 1 month after. The drug kills the parasites acquired the month before.

Side effects shouldn't occur if the drug it's administered in low dosages. Higher dosage of Ivermectin can be administered as a cure for skin mites. Some canine breeds like Collies, Shetland sheepdogs, Australian shepherds, and Old English sheepdogs may require a blood test before using Ivermectin as these breeds are hypersensitive and genetically sensitive to this medication. If your dog is one of these breeds and it was administered Ivermectin you should supervise your pet for the following 8 hours after using the drug. If you notice weakness, staggering, dilated pupils or trembling you should immediately contact your veterinarian.

Melarsomine Dihydrochloride, marketed under the brand name Immiticide, is used as a treatment for heartworm disease. It's available as a powder which is mixed with sterile water before use and it kills immature and adult heartworms in dogs. It's administered by deep intramuscular injection in the lumbar back muscle twice in 48 hours depending on the severity of the case. Immiticide is contraindicated in dogs with very severe heartworm disease until the heartworms are removed surgically.

After the administration of the drug, irritations were observed at the injection site. Other side effects that may occur are swelling, tenderness, and reluctance to move, coughing, gagging, depression, lethargy, lack of appetite, fever, lung congestion and vomiting. Firm nodules can persist indefinitely. Even after the death of the worms the dog may still suffer from coughing, fever, or weakness. The owner has to keep the dog at cage rest for the next 4-6 weeks otherwise the dog may suffer of pulmonary embolism. A retest must be done 4 months after treatment and after which, if everything is clear, you should begin a prevention treatment for heartworm disease.