Dangers of Heartworm Medicine

Heartworm disease (Dirofilaria immitis) affects both dogs and cats. The parasite infects the mosquito when it bites an infected animal and uses it as an intermediary host, offloading its larva when the mosquito bites an uninfected animal. Heartworm can be fatal if it is not treated soon after infestation.
    • Your Pet and Heartworm Medications

    Heartworm Parasite

    • Once the parasite is in your pet's bloodstream, the microfilariae begin to grow and burrow deeper into the animal's veins until they reach the right side of the heart, where they will eventually reproduce. Adult heartworms can reach a length of up to 12 inches. Female heartworms can produce thousands of live microfilariae in a single day. These will circulate throughout your pet's bloodstream for up to three years.

    Heartworm Medications

    • There are two types of treatment for heartworm; oral medications and topical applications. Whichever you choose, they are usually applied monthly. Your veterinarian will usually recommend you use one for your pet to prevent heartworm infection. These medications protect your pet by killing any microfilariae that may enter the bloodstream before they are able to mature and reproduce. Many heartworm preventive medications also prevent tapeworms, hookworms, roundworms and whipworms; some also help prevent fleas and ticks.

    Active Ingredients

    • The most common active ingredient in pet heartworm medication is Ivermectin. It is currently the most effective substance of its kind for preventing and killing a wide range of parasites. There are, however, some alternatives such as Selamectin, Mibemycin oxime and moxidectin in combination with imidacloprid.

    Side Effects

    • Side effects in dogs have been reported from oral use of Ivermectin, particularly in collies and sheep dogs. This is believed to be due to a genetic sensitivity. Symptoms may include whining, lethargy, lack of appetite, vomiting, diarrhea, lack of coordination, excessive salivation and seizures. Side effects from topical medications can include skin allergic reaction, drooling, muscle tremors, vomiting and diarrhea.

    Natural Alternatives

    • A number of vets believe that heartworm medications are more harmful for your pet than good. They suggest that the key to heartworm prevention is to use herbal and nutritional supplements to maintain your pet's overall health and stimulate a healthy metabolism. Some of the herbal treatments recommended include spearmint, garlic, mugwort, turmeric root, clove flower bids and black walnut. If you wish to stop using your current heartworm medication and change to an herbal treatment you should consult your vet.