Short answer: Immiticide.
- Melarsomine is the drug of choice for the first stage and is effective for killing adult heartworms living in the arteries of the lungs.
- Melarsomine is an arsenic-based drug. Although these drugs are known to kill adult heartworms, the exact method of the killing action is unknown.
- Melarsomine is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.
Long answer another time!