Melarsomine (Immiticide) treatment for adult heartworms in dogs requires staged intramuscular injections with strict exercise restriction, creating a welfare-significant treatment protocol that requires careful management.
Heartworm treatment welfare encompasses the acute welfare of the treatment process and the welfare-saving outcome of eliminating a parasite that causes progressive cardiopulmonary disease. Treatment injections cause local pain and soreness that analgesic management can reduce. Eight weeks of strict cage rest imposes behavioral restriction on animals adapted to activity - the welfare cost of confinement is real, particularly for high-energy breeds. The risk of pulmonary embolism from exercise during treatment makes this restriction medically essential; dogs that exercise during treatment can die suddenly as dead worms embolize to the lungs. The best welfare outcome is preventing the situation entirely through year-round prevention.