How much does heartworm treatment cost?
Last updated: May 2026 · Methodology · Sources
Treating heartworm in a dog costs $600–$3,000, averaging around $1,000, and can reach $6,000 in advanced cases. The melarsomine injection series is the main expense. Monthly prevention at $5–$15 is dramatically cheaper.
Cost components
| Component | Low | Typical | High |
|---|---|---|---|
| Confirmatory testing + bloodwork | $100 | $200 | $400 |
| Chest X-rays (staging) | $150 | $250 | $450 |
| Melarsomine injection series (the core treatment) | $500 | $1,000 | $1,500 |
| Antibiotics, steroids, hospitalization | $150 | $400 | $900 |
| Total typical course (size-dependent) | $600 | $1,200 | $3,000 |
Teal marker = typical cost · shaded band = low–high range. Biggest cost drivers first.
Heartworm treatment takes 4–6 months and is dosed by body weight, so large dogs cost more. Cats can't take melarsomine — feline heartworm is managed supportively, not cured.
What drives the cost
- Dog size — melarsomine is weight-dosed, so big dogs cost more.
- Disease stage — advanced (Class 3–4) cases need more staging, hospitalization, and monitoring.
- Strict rest period — dogs must be exercise-restricted for weeks during treatment to avoid fatal clots, which sometimes means boarding or crating.
Why it's so much more than prevention
Monthly heartworm prevention costs about $5–$15 ($60–$180 a year), while treatment runs $600–$3,000 and carries real risk. Skipping prevention to save money is the most expensive bet in dog care — especially in the U.S. South and Southeast, where heartworm is endemic.
Cats are different
There's no approved drug to kill adult heartworms in cats, so feline heartworm is managed with supportive care rather than cured. Prevention is the only real protection for cats too.
Cost with vs. without insurance
Heartworm treatment is covered by accident-and-illness insurance if the policy predates the diagnosis. Worked example for a $1,200 treatment course:
| Scenario | You pay |
|---|---|
| No insurance (full bill) | $1,200 |
| Insurance, 80% reimbursement, $250 deductible met | $190 |
| Prevention instead (per year) | $60–$180 |
Note that routine heartworm prevention usually needs a wellness add-on; treatment of an infection is covered by the core illness policy. Run the trade-off in our insurance vs. savings calculator, or build a full visit estimate in the vet bill calculator.
Related guides
- Dog bloodwork cost — heartworm testing is a blood test.
- Dog X-ray cost — chest films stage the disease.
- Dog vaccine cost — where preventive care fits in the budget.
- Dog cost calculator — full annual + lifetime ownership estimate.
FAQ
How much does heartworm treatment cost?
$600–$3,000 for dogs, averaging about $1,000, and up to $6,000 for advanced cases. The melarsomine injection series is the biggest single cost.
Why is heartworm treatment so expensive?
It takes 4–6 months, requires weight-dosed melarsomine injections, chest X-rays, bloodwork, antibiotics, and strict rest. Large dogs and advanced cases cost the most.
How much does heartworm treatment cost for cats?
There's no drug to kill adult heartworms in cats, so feline cases are managed with supportive care rather than cured. Costs vary widely; prevention is the only reliable protection.
Is it cheaper to prevent or treat heartworm?
Prevention is dramatically cheaper — about $5–$15 a month versus $600–$3,000 to treat. Prevention also avoids the health risks that come with treatment.
Does pet insurance cover heartworm treatment?
Yes, accident-and-illness plans cover treatment of a heartworm infection if the policy predates diagnosis. Routine monthly prevention usually requires a wellness add-on.