VetCostCalc

Heartworm Treatment Cost: $1,000–$3,500 for Dogs (2026)

Heartworm treatment costs $1,000–$3,500 for the full protocol: three melarsomine injections over 60 days, antibiotics, steroids, and strict cage rest. Monthly prevention costs $6–$18. A lifetime of prevention is cheaper than one treatment. The American Heartworm Society reports heartworm in all 50 states — this isn't a regional problem anymore.

Cost at a Glance

Dog

$0–$0

Private vet, national avg

CA / NY

$0–$0

25–35% above avg

What Affects the Cost

  • Treatment is a 60-day process, not a single visit. Day 1: first injection. Day 30: second injection. Day 31: third injection. Plus 30 days of doxycycline before injections start. Total treatment timeline: ~90 days with strict exercise restriction.
  • Cage rest is not optional. Dead heartworms break into fragments that travel to the lungs. Exercise increases blood flow and can cause fatal pulmonary embolism. Your dog must be confined for 6–8 weeks after the last injection. This is the hardest part for most owners.
  • Prevention costs $72–$216/year. Treatment costs $1,000–$3,500 once, plus the risk of permanent heart/lung damage. There's no scenario where skipping prevention saves money.
  • No approved treatment for cats. Cats get supportive care and wait for worms to die naturally (2–4 years). Even 1–2 worms can kill a cat. Monthly prevention is the only protection.
  • Rescue dogs from the South are high-risk. Heartworm prevalence is highest in the Gulf Coast states and Mississippi River valley. Always test rescue and adopted dogs regardless of stated history.

Cost by State

National average adjusted by state cost-of-living index. Urban areas run ~30% higher than suburban; rural ~25% lower.

State Dog vs. Avg
Alabama $0–$0 -18%
Alaska $0–$0 +25%
Arizona $0–$0 -5%
Arkansas $0–$0 -20%
California $0–$0 +35%
Colorado $0–$0 +10%
Connecticut $0–$0 +25%
Delaware $0–$0 +5%
Florida $0–$0 0%
Georgia $0–$0 -10%
Hawaii $0–$0 +40%
Idaho $0–$0 -10%
Illinois $0–$0 +5%
Indiana $0–$0 -12%
Iowa $0–$0 -15%
Kansas $0–$0 -15%
Kentucky $0–$0 -15%
Louisiana $0–$0 -15%
Maine $0–$0 0%
Maryland $0–$0 +15%
Massachusetts $0–$0 +30%
Michigan $0–$0 -10%
Minnesota $0–$0 0%
Mississippi $0–$0 -22%
Missouri $0–$0 -15%
Montana $0–$0 -8%
Nebraska $0–$0 -12%
Nevada $0–$0 +5%
New Hampshire $0–$0 +10%
New Jersey $0–$0 +25%
New Mexico $0–$0 -12%
New York $0–$0 +30%
North Carolina $0–$0 -8%
North Dakota $0–$0 -12%
Ohio $0–$0 -10%
Oklahoma $0–$0 -18%
Oregon $0–$0 +10%
Pennsylvania $0–$0 0%
Rhode Island $0–$0 +10%
South Carolina $0–$0 -12%
South Dakota $0–$0 -15%
Tennessee $0–$0 -12%
Texas $0–$0 -8%
Utah $0–$0 -5%
Vermont $0–$0 +5%
Virginia $0–$0 +5%
Washington $0–$0 +15%
West Virginia $0–$0 -20%
Wisconsin $0–$0 -8%
Wyoming $0–$0 -10%

Data: AVMA fee surveys, BLS cost-of-living data. Ranges reflect typical private practice prices — low-cost clinics and university teaching hospitals charge significantly less.

Common Questions

How much does heartworm treatment cost for a dog?
Heartworm treatment costs $1,000–$3,500 for the full protocol. The treatment involves three injections of melarsomine (Immiticide) given over 60 days, plus steroids, antibiotics (doxycycline for 30 days), and strict cage rest. Pre-treatment workup (X-rays, bloodwork, heartworm antigen test) adds $300–$500. Severe cases with heart or lung damage may need hospitalization ($500–$1,500 additional). Monthly heartworm prevention costs $6–$18 per month — doing the math, a lifetime of prevention is cheaper than one round of treatment.
Can cats get heartworm?
Yes, but it's different. Cats are not natural hosts — they typically have 1–3 adult worms vs 15–250 in dogs. There is no approved heartworm treatment for cats (melarsomine is toxic to cats). Treatment is supportive: manage symptoms and wait for the worms to die naturally, which takes 2–4 years. Even a small number of worms can kill a cat because their hearts and lungs are so small. Monthly prevention ($8–$15 for cats) is the only real option. Indoor cats still get heartworm — mosquitoes come inside.
What happens if I don't treat heartworm in my dog?
Untreated heartworm is fatal. Adult heartworms live in the pulmonary arteries and right side of the heart. They cause progressive heart failure, lung disease, and organ damage. A dog with a heavy worm burden (30+ worms) develops caval syndrome — a life-threatening condition where worms block blood flow through the heart. Even moderate infections cause exercise intolerance, coughing, and fluid buildup in the abdomen. Early-stage heartworm (Class 1) has a 98% treatment success rate. Class 4 (caval syndrome) requires emergency surgical worm extraction and has high mortality.
How much does monthly heartworm prevention cost?
Monthly heartworm prevention costs $6–$18 per month for dogs and $8–$15 for cats. Heartgard Plus (ivermectin) is the most popular brand at $8–$15/month for dogs depending on weight. Simparica Trio and NexGard Plus combine heartworm prevention with flea/tick protection for $18–$25/month. Generic ivermectin-based preventives cost $6–$10/month. Over a dog's lifetime (10–14 years), prevention costs $720–$3,000 total. One round of heartworm treatment costs $1,000–$3,500. The math is obvious.

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Data: Nationwide Pet Insurance Claims Data, AVMA U.S. Pet Ownership and Demographics Sourcebook, APPA National Pet Owners Survey, VECCS Emergency Cost Data

Last updated: March 2026

How we calculate this · Pet insurance terms vary. Read the policy carefully, especially exclusions for pre-existing and breed-specific conditions.

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