Heartworm medicine for dogs

Heartworm medicines are of great use, since they effectively help to fight heartworm disease in dogs, which may result in their death. Dogs suffering from heartworm disease have worms the size of spaghetti, thriving in their hearts and their blood streams.

Mosquitoes are responsible for passing on heartworms to dogs. Thus, dogs are prone to heartworm disease, irrespective of their age, locale, and sex. While there are treatments for diagnosed dogs, prevention is much better than the cure. There are good preventive heartworm medications too.

Prevention is not the same as treatment, since preventive heartworm medicines vary a lot from treatment of heartworm medications. Several preventive medicines come as pills, topical creams, and chewables, while treatment medicines are muscle injections in combination with certain pills.

Preferred Heartworm Medications:

Iverhart Plus

This is a prescription drug usually available as pork liver flavored chewable pills. The general dosage of Iverhart Plus for dogs weighing around 25 pounds is 68mcg/57mg, for dogs between 26-50 pounds, the ideal dosage is 136mcg/114mg, and for dogs weighing between 51-100 pounds, the dose is 272mcg/227mg. Dogs weighing more than 100 pounds need a mixture of Iverhart Plus pills.

Usually, vets ask dog owners to give Iverhart Plus once every month to prevent the condition of heartworm in dogs. This heartworm medicine also prevents roundworm and hookworm in dogs. A vital thing you need to consult with vets is a possible allergic reaction dogs may have, to this medication.


This is a prescription heartworm medicine available as unflavored pills. The common dosage of Heartgard for dogs weighing around 25 pounds is 68mcg and 136 mcg for dogs weighing between 26-50 pounds, and finally for dogs weighing between 51-100 pounds it is 272 mcg.

Vets recommend this medicine once a month to prevent heartworm disease in dogs.


Similar to Iverhart Plus and Heartgard, Interceptor is also a prescription heartworm medicine approved by the FDA. This heartworm medicine is usually available as flavored chewable pills.

Generally, the dosage of Interceptor for dogs between 2-10 pounds is 2.3mg and 5.75 mg for dogs between 11-25 pounds, 11.5 mg for dogs weighing between 26-50 pounds, and 23 mg for dogs ranging between 51-100 pounds. It is good to give these doses once in a month.


This is the only heartworm medicine, which effectively kills grown-up heartworms in dogs. The medicine contains an arsenic-based element called melarsomine.

As always, talk to your vet to determine which medicines are more appropriate for your dog.