Heartgard is given once a month year round for the prevention of heartworm disease. The usual dose of Heartgard in dogs up to 25 pounds is 68mcg, for 26-50 pounds is 136mcg and for 51-100 pounds is 272mcg. Dogs over 100 pounds are given a combination of tablets. The usual dose of Heartgard in cats 5 pounds or less is 55mcg and for cats 6-15 pounds is 165mcg. The chewable tablets should be chewed. They are not meant to be swallowed whole. For dogs that normally swallow treats whole, the tablet can be broken into pieces. As an alternate to year round dosing, this medication can be given during the mosquito season and for one month after the season ends.

The side effects of Heartgard are rare at the recommended heartworm prevention dose. Higher doses in dogs may cause tremors, dilated pupils, and loss of body weight or death. Side effects in cats include agitation, loss of appetite, staggering, dilated pupils, tremors, blindness and disorientation.

Contact your veterinarian or veterinary emergency room. Symptoms of overdose may include vomiting, diarrhea, and incoordination in dogs. The symptoms of overdose in cats may include disorientation, tremors, incoordination, and blindness.

All dogs should be tested for existing heartworm infection before starting treatment with Heartz which is not effective against adult D. immitis. Infected dogs must be treated to remove adult heartworms and microfilariae before initiating a programme with Heartz.

To prevent canine heartworm disease by eliminating the tissue stage of heartworm larvae (Dirofilaria immitis) for a month (30 days) after infection and for the treatment and control of ascarids (Toxocara canis, Toxascaris leonina) and hookworms (Ancylostoma caninum, Uncinaria stenocephala, Ancylostoma braziliense).

Heartgard is an anthelminthic (dewormer) used for the prevention of heartworm disease in dogs and cats. Heartgard is also used for the control of hookworm in cats. Combined with pyrantel pamoate (Heartgard Plus), it also protects against hookworm and roundworm in dogs.

This medication should not be used in animals allergic to it. Use with caution in Collies. Heartworm testing should be performed prior to the start of prevention therapy. If the animal is off Heartgard for 6 months or less, start the medication and test after 6 months since microfilaria, that take 6 months to mature, will result in a positive test result. Because humans can contract hookworm from animals, it is important to maintain good personal hygiene. It is also important to eliminate fleas on the pet and in the household and to not feed the pet rodents or uncooked meat or fish. To prevent reinfection, daily cleanup of stools is recommended.