Duluth-based Merial, distributor of Immiticide, the only FDA-approved drug available to treat adult heartworms in dogs, sent letters earlier this month to veterinarians informing them of the depletion of inventory. The news was not unexpected; the company warned of production problems as far back as December 2009.

Immiticide is the only drug licensed or used to treat adult heartworms in dogs, and Merial is the only company who makes this product.

Because of the shortage, veterinarians can no longer order Immiticide from distributors, in order to prevent stockpiling.

Merial spokesman Steve Dickinson said “technical issues” have halted the production of Immiticide by a third-party supplier. The company is “trying as hard as [it] can” to resume production or find an alternative supplier, he said.

Dickinson said one of the problems is that the active ingredient in Immiticide, melarsomine, is difficult to manufacture. Melarsomine, a derivative of arsenic, is effective at killing adult heartworms — a parasitic roundworm transmitted by mosquitoes — that infest animal arteries and can cause death.

Currently, Merial has no Immiticide to sell to veterinarians, said Dickinson. He did not know when production would resume, saying only that the problem could last several weeks or months.

Those in the animal health care field say that while the lack of Immiticide is a problem, it’s no cause for panic.

Alternative treatment for heartworm

A combination of 2 drugs, ivermectin (in Heartgard) and doxycycline (an antibiotic used for kennel cough), weakens and sterilizes adult heartworms and will slowly kill them.

The time is longer based on the number of Heartworms, as well as the age of the Heartworms.

Merial has said that a limited supply of immiticide is available on a case by case basis- your Veterinarian needs to contact the company to see if they can release the drug to treat your dog ( if infected)

P.S. There are a number of drugs currently on a short supply- certain antibiotics, along with drugs used to treat cancer.

Immiticide is now part of that list.

Your BEST option is to keep your dog or cat healthy in the first place.

Use some alternate options when possible.

And feed some type of supplement to maintain their health.

Here is what I feed my own dogs and cats- and you can now get a trial bottle for 50% OFF: