Worm Medicine for Dogs

The right worm medicine keeps your dog free of parasites all her life.
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Keeping your dog parasite-free is vital to ensuring her health in the long term. With the variety of worms that dogs can contract, you may need a combination of medicines to protect your dog. Your veterinarian will recommend the best option for the risks of the area where you live.


Hailed as an important discovery in 1987 when it was first approved, ivermectin is a chemical developed to paralyze a range of parasites, including worms. It is prescribed commonly to get rid of worms in humans and animals. It works by paralyzing the worms’ larvae, which causes them to die before they can reach adulthood. This prevents the growth of a large number of worms that can feed off the dog and cause illness. Veterinarians prescribe ivermectin for heartworm, whipworm, hookworm and roundworm, as well as for ear mites and other parasitic arthropods. Ivermectin for dogs is sold under the names Ivomec and Heartgard.


This drug belongs to the group of medicines called anthelmintics, which stun and then expel worms and other parasites from the body. It works on a range of worm species, but is particularly effective for flatworm species such as tapeworms, which can be passed on to humans, where they cause cysts in the brain, liver and lungs that can result in death. Praziquantel for dogs comes in products sold under the names Drontal, Droncit and Drontal Plus.


Worm medicines made with mylbemycin are antibiotics that kill parasites by disrupting their neurotransmitters. Dogs with whipworm, roundworm and hookworm do well with mylbemycin, which they take in the form of tablets once a month. The dosage eliminates any parasites in the dog’s system at the time, to prevent them from reaching adulthood and breeding. Mylbemycin sells under the brand names Interceptor and Sentinel.


Fenbendazole is another anthelmintic drug, formulated to work on a wide variety of intestinal parasites. Sold under the names Panacur and Safe-Guard, it is a broad-spectrum worm medicine that protects dogs from hookworm, roundworm, tapeworm, whipworm and other parasites found in the stomach and the dog’s respiratory system. It comes in a paste, granules and a suspension liquid; the paste and granules can be mixed with the dog’s food, and the liquid given using a syringe.


Most worm medicines have a degree of toxicity that kills the parasites, and can be harmful to dogs in the wrong quantities. For example, certain breeds carry a gene mutation that make them particularly sensitive to ivermectin. These include the collie breeds, such as Australian shepherds, Shelties, border collies and old English sheepdogs. Such dogs show neurological effects after taking just 2 percent of the dose needed to affect other breeds. The symptoms of toxicity include extreme salivation, breathing difficulties, blindness, coma and death. Always consult your veterinarian before giving your dog any type of worm medicine.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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