Ivermectin: Generic Heartgard for Dogs

Generic heartgard is a term used for ivermectin. Both the generic Heartgard and Heartgard itself protect against heartworms. As a conscious dog owner, you should be researching whether there are significant differences between Heartgard and its generic equivalent, Ivermectin.

Generic Heartgard vs. Branded Heartgard Medicine

Generic drugs are drugs that are not protected by a patent, which makes the medicine cheaper. Generally, when a new active ingredient is invented, it is protected by a patent for a number of years. The original formula containing the active ingredient is protected, too. When the patent expires, other companies start producing drugs which have to be bioequivalent with the original (have the same dose of the active ingredient and the same main characteristics and are administered in the same way). These are called generic drugs.

The original Heartgard contains ivermectin as an active ingredient. The generic ivermectin-based drugs, such as Nuheart or Valuhart, contain the active ingredient ivermectin in the same dose as Heartgard, and will have the same effects as the original. They are all administered orally, although some might be chewable while others have to be swallowed.

Characteristics of Generic Heartgard

Macrocyclic lactones (Mls) are a group of chemicals commonly used to prevent heartworm. Ivermectin belongs to this group. Streptomyces avermitilis is a bacterium that produces a sugar from which ivermectin is derived. In different doses, ivermectin can fight internal and external parasites in cattle, horses or house pets. Ivermectin stops the worm's neural transmission by killing it.

Ivermectin-based drugs are prescribed once a month, because they can kill any larvae. Heartgard (and all ivermectin-based drugs) is known to have a reach-back effect consisting of its capacity to kill larvae that have infested the organism up to four months prior to administration, provided that the drug is administrated continuously for 12 months.

Adverse Reactions to Generic Heartgard

All macrocyclic lactones are safe to be administered to mammals. Allergies might occur more due to the base of the formulation, rather than to ivermectin.

In dogs, the doses that can be used are relatively small, so generic Heartgard is effective in killing the larvae of heartworm, but not adult worms which have already migrated to the heart. Ivermectin becomes toxic for dogs only if administered in doses over 100 times larger than the dose required for preventing heartworm.

Ivermectin-based drugs are not recommended in puppies younger than 6 weeks. This is due to the fact that the blood-brain barrier in puppies is not yet closed, and ivermectin can enter the brain and cause nervous symptoms.

Because heartworm can be deadly, it is highly recommended that dog owners use preventative drugs. These have to be administered all year round in some regions (hot, wet regions, where there are mosquitoes in all seasons and the risk of contamination is higher) or for a few months each year. Ivermectin-based drugs come in formulas that fight heartworm as well as other parasites, so before choosing the original or generic Heartgard, it is best to consult your veterinarian and find out which works best for your pet.