Dog Heartworm Treatment Cost

The full heartworm protocol typically adds up to $750–$2,200, spread over several visits. The standard protocol includes diagnostic testing ($35–$75), chest X-rays ($125–$250), 30 days of doxycycline ($30–$150), a series of melarsomine (Immiticide) injections ($500–$1,500), and follow-up testing. Small dogs land lower; large dogs pay more due to weight-based medication dosing. Severe cases needing hospitalization or oxygen therapy can reach $3,000–$6,000.

The American Heartworm Society protocol typically spans 3–4 months: (1) Diagnostic workup — heartworm antigen test, confirmatory microfilaria test, chest X-rays, and blood work ($200–$500). (2) Pre-treatment — 30 days of doxycycline ($30–$150) plus monthly heartworm preventive ($6–$18/dose). (3) Melarsomine injections — one injection, then two more 24 hours apart one month later ($500–$1,500 for all three). (4) Strict exercise restriction for 6–8 weeks post-injections. (5) Follow-up heartworm test at 6 months ($35–$75).

The melarsomine injections alone cost $500–$1,500 for the standard three-injection series. The drug is injected deep into the lumbar muscles and requires veterinary monitoring. Pricing varies by dog weight (larger dogs need higher doses), geographic location, and whether your vet keeps the drug in stock — supply shortages have historically caused price spikes. Some clinics charge a flat fee for the full injection series; others charge per injection.

The full treatment protocol costs $750–$2,200.Monthly heartworm prevention ($6–$18/month, or $72–$216/year) is far cheaper than treatment — one round of treatment costs roughly 3–10 years of prevention.

Some options to reduce costs: humane societies and rescue organizations offer subsidized treatment ($225–$600 in some areas). Veterinary teaching hospitals charge 30–50% below private practice rates. The "slow kill" method (monthly preventive only, no Immiticide) is not recommended by the American Heartworm Society — it takes 1–2+ years, leaves adult worms damaging the heart during that time, and is not truly cheaper once years of preventive and monitoring are factored in. CareCredit and Scratchpay offer payment plans.

Most comprehensive pet insurance plans cover heartworm treatment at 70–90% after deductible — diagnostics, injections, hospitalization, and follow-up are all eligible. Key exclusion: dogs diagnosed with heartworm before enrollment are excluded as pre-existing. Some policies also exclude treatment if the dog was not on documented monthly preventive (check your policy's "preventable condition" clause). Enroll and keep preventive current before any positive test.

Monthly prevention costs $6–$18/dose ($72–$216/year) depending on dog size and product. The full treatment protocol costs $750–$2,200. Popular preventives include Heartgard ($6–$12/month), Simparica Trio ($18–$25/month, also covers fleas and ticks), and ProHeart 6/12 injection ($50–$150 per 6- or 12-month dose administered at the vet).