According to the drug manufacturer Merial, technical issues at one of its production plants have temporarily interrupted its ability to produce the only medication (Immiticide®) approved to treat heartworm disease in dogs.
Heartworm disease is a potentially fatal condition when not treated promptly. The American Heartworm Society (AHS) has put together a management plan to deal with dogs that are diagnosed with heartworm disease while Immiticide® remains unavailable. The following is modified from the AHS guide for disease management during the unavailability of this drug.
1. Verify that a dog is actually heartworm positive by performing a second heartworm antigen test produced by a different manufacturer.
2. Perform a microfilariae test. Microfilariae are microscopic larval heartworms that circulate in an infected dog’s bloodstream. If a dog has microfilaria, he should be pretreated with corticosteroids and possibly an antihistamine before starting on a heartworm preventative to reduce the risk of an adverse reaction. All heartworm positive dogs should be placed on a heartworm preventative ASAP to prevent them from being infected with more worms.
3. Treat heartworm positive dogs with doxycycline to shorten the lifespan of adult heartworms, disrupt the transmission of heartworms to other dogs through mosquito bites and reduce the side effects associated with the death of worms in the dog’s heart and lungs.
4. Restrict all activity and limit all exercise in dogs with heartworm disease.
5. Treat any symptoms associated with heartworm disease on an as needed basis (e.g., fluid build-up can be reduced using diuretics).
This crisis underscores the importance of protecting dogs from heartworm disease by giving them an effective monthly heartworm preventative all year round.