Immiticide shortage update

A shortage of Immiticide will cause the heartworm drug to be unavailable for several weeks to several months, according to Merial, the company that sells Immiticide.

Merial said in a statement that the company that manufactures Immiticide (melarsomine dihydrochloride) is "experiencing technical issues in their plant that will temporarily affect their ability to provide finished product to us." The company said its inventory of Immiticide is depleted, but that it is working to identify a possible alternate source of supply.

"Merial and the IMMITICIDE manufacturer fully understand the critical need for the product and regret this outage. We are working together to return to full supply as quickly as possible," the company said.

Immiticide is the only heartworm adulticide available to treat heartworm disease in dogs. While Merial works out the next steps, the American Heartworm Society (AHS) has put together a detailed plan on its website for veterinarians with heartworm-positive patients.

Below is an outline of what the AHS recommends, but the more detailed, step-by-step plan with recommended dosages and timing is available at AHS President Wallace Graham, DVM, said the goal of the management plan is not to eliminate the disease, but to manage the patient until Immiticide is available again.

The goals of the interim plan endorsed by AHS are to reduce potential pathology from the infection; maintain the health of the heartworm-positive dog until it can be appropriately treated; and prevent additional heartworm infection of the dog.

Management steps include:

  • Verification of heartworm status
  • Pretreatment of heartworm-positive dogs to prevent shock
  • Careful administration of a macrocyclic lactone heartworm preventive, followed by clinical observation for at least eight hours
  • Continuous administration of a heartworm preventive on the regular dosing schedule
  • Administration of doxycycline on a one-month-on/two-months-off schedule
  • Restricted activity and exercise of the heartworm-positive dog throughout the management period
  • Medical treatment of symptomatic heartworm infection to relieve signs of respiratory disease, with surgical options weighed for dogs exhibiting cardiovascular compromise
  • Retesting for heartworm status before treatment with adulticide treatment once the product is again available.

Veterinarians who have technical questions for Merial may contact Veterinary Technical Solutions team at 1-888-637-4251, Option 3.

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