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Key takeaways
- A complete course costs $700–$3,500 all-in, depending on the dog's weight and disease class.
- Weight drives the drug cost: $700–$1,200 for a small dog, $1,000–$1,800 for a medium one, $1,500–$3,500 for a large one.
- Severity matters as much as size: Class 1 runs $400–$800, Class 4 (caval syndrome) can exceed $5,000.
- Prevention costs $75–$215 a year versus $1,500+ for treatment — roughly a 10:1 difference.
Heartworm treatment cost breakdown
Treatment is a staged protocol, not a single injection. The American Heartworm Society's standard regimen is one melarsomine injection on day 60, then two more on days 90 and 91, twenty-four hours apart, preceded by a 28-day course of doxycycline. Each stage is billed separately, which is why totals vary so widely.
| Service | Low | Average | High | Range ($0–$6,500) |
|---|---|---|---|---|
| Heartworm antigen test | $35 | $55 | $100 | |
| Pre-treatment bloodwork (CBC / chemistry) | $80 | $130 | $200 | |
| Chest X-rays (2 views) | $150 | $225 | $400 | |
| Doxycycline, 28-day course | $10 | $60 | $150 | |
| Melarsomine injection (each) | $100 | $150 | $200 | |
| Melarsomine series — 3 injections (drug only) | $300 | $450 | $600 | |
| Hospitalization & monitoring (per injection day) | $150 | $275 | $400 | |
| Echocardiogram (severe cases) | $300 | $600 | $1,000 | |
| Caval syndrome surgical extraction | $3,000 | $4,500 | $6,000+ |
What changes the price
Full protocol, medium dog by state
Prices track local labor and rent costs. The figures below are modeled, not surveyed: we apply a regional cost index to the national figure above, so treat them as a guide to how far your state sits from the national average rather than as quotes from local providers.
| State | Full protocol, medium dog | Annual prevention | vs. national avg |
|---|---|---|---|
| New York | $1,960 | $203 | +40% |
| California | $1,890 | $196 | +35% |
| Washington | $1,680 | $174 | +20% |
| Florida | $1,540 | $160 | +10% |
| Illinois | $1,470 | $152 | +5% |
| Arizona | $1,428 | $148 | +2% |
| Pennsylvania | $1,428 | $148 | +2% |
| Texas | $1,400 | $145 | 0% |
| Georgia | $1,260 | $131 | −10% |
| Ohio | $1,190 | $123 | −15% |
Show all 50 states + D.C.
| State | Full protocol, medium dog | Annual prevention | vs. national avg |
|---|---|---|---|
| Hawaii | $1,960 | $203 | +40% |
| New York | $1,960 | $203 | +40% |
| Washington, D.C. | $1,932 | $200 | +38% |
| California | $1,890 | $196 | +35% |
| Massachusetts | $1,848 | $191 | +32% |
| New Jersey | $1,792 | $186 | +28% |
| Connecticut | $1,750 | $181 | +25% |
| Alaska | $1,708 | $177 | +22% |
| Washington | $1,680 | $174 | +20% |
| Maryland | $1,652 | $171 | +18% |
| Rhode Island | $1,610 | $167 | +15% |
| New Hampshire | $1,568 | $162 | +12% |
| Oregon | $1,568 | $162 | +12% |
| Colorado | $1,540 | $160 | +10% |
| Florida | $1,540 | $160 | +10% |
| Vermont | $1,512 | $157 | +8% |
| Virginia | $1,512 | $157 | +8% |
| Delaware | $1,470 | $152 | +5% |
| Illinois | $1,470 | $152 | +5% |
| Maine | $1,470 | $152 | +5% |
| Nevada | $1,470 | $152 | +5% |
| Arizona | $1,428 | $148 | +2% |
| Minnesota | $1,428 | $148 | +2% |
| Pennsylvania | $1,428 | $148 | +2% |
| Texas | $1,400 | $145 | 0% |
| Montana | $1,372 | $142 | −2% |
| Utah | $1,372 | $142 | −2% |
| Idaho | $1,330 | $138 | −5% |
| Michigan | $1,330 | $138 | −5% |
| North Carolina | $1,330 | $138 | −5% |
| Wyoming | $1,330 | $138 | −5% |
| Wisconsin | $1,302 | $135 | −7% |
| New Mexico | $1,288 | $133 | −8% |
| North Dakota | $1,288 | $133 | −8% |
| South Carolina | $1,288 | $133 | −8% |
| Georgia | $1,260 | $131 | −10% |
| Louisiana | $1,260 | $131 | −10% |
| Nebraska | $1,260 | $131 | −10% |
| South Dakota | $1,260 | $131 | −10% |
| Tennessee | $1,260 | $131 | −10% |
| Missouri | $1,246 | $129 | −11% |
| Alabama | $1,232 | $128 | −12% |
| Indiana | $1,232 | $128 | −12% |
| Kansas | $1,232 | $128 | −12% |
| Iowa | $1,218 | $126 | −13% |
| Kentucky | $1,218 | $126 | −13% |
| Arkansas | $1,204 | $125 | −14% |
| Oklahoma | $1,204 | $125 | −14% |
| Ohio | $1,190 | $123 | −15% |
| Mississippi | $1,176 | $122 | −16% |
| West Virginia | $1,176 | $122 | −16% |
How to pay less
Ask about an outpatient injection schedule where medically appropriate. Going home the same day instead of overnight observation after each of the three doses can save $300–$800.
Fill doxycycline and prednisone at a human pharmacy with a discount coupon. The 28-day doxycycline course can drop from a clinic's $60–$150 to $10–$25.
Ask about nonprofit and shelter heartworm assistance programs and clinic financing (CareCredit, Scratchpay). Many rescue-affiliated clinics treat for $400–$700 all-in, and moving to prevention afterward ($75–$215 a year) avoids a repeat bill.
How we calculated these numbers
Frequently asked questions
Why does the vet prescribe doxycycline before the injections?
Doxycycline kills Wolbachia bacteria living inside the worms, which reduces inflammation and the risk of a post-injection blood clot. It's a standard 28-day pre-treatment costing $10–$150.
Is the slow-kill method a safe way to save money?
It's cheaper on medication ($150–$300) but takes 12–27 months, leaves adult worms damaging the heart and lungs throughout, and the American Heartworm Society recommends its own protocol — doxycycline, then melarsomine on day 60 and again on days 90 and 91 — instead.
Why must the dog be exercise-restricted during treatment?
Dying worms break apart and lodge in the lung arteries. Strict rest for three to four months after treatment is the main way to prevent a fatal blood clot.
How much cheaper is prevention than treatment?
Prevention costs $75–$215 a year including the annual test, versus $1,500–$3,500 for a full treatment — roughly 5–10% of the cost.
A note on these figures. Prices are national estimates compiled from the published sources listed below and will differ from what your local provider quotes. CostFlock is not a veterinary practice and nothing here is medical advice — always discuss treatment options and costs with a licensed veterinarian.
- VetCostGuide — Dog heartworm treatment cost, Immiticide protocol (2026)
- PetMD — How much does heartworm treatment cost for dogs? (2025)
- GoodRx — Heartworm treatment cost for dogs (2025)
- American Heartworm Society — The AHS protocol vs. slow kill (2025)