Heartworm transmission has been documented nationwide.
COMPANION HEALTH LIBRARY · PREVENTATIVE GUIDE · UPDATED AUG 15, 2026
Find the coverage.
See the gaps.
A practical way for pet owners to compare major flea, tick, heartworm, and intestinal-parasite preventatives currently marketed in the United States.
Explore 32 productsFor informed conversations with your veterinary team
DOG
CAT
FTHLOCATION CHANGES EXPOSURE—NOT THE NEED FOR A PLAN
Where your pet lives changes the risk—not whether risk exists.
Indoor living, fenced yards, and gated communities can reduce certain exposures, but they cannot eliminate them. Mosquitoes can enter homes, ticks may be carried in by people or animals, fleas can establish indoor populations, and wildlife can introduce parasites into maintained yards.
An N.C. State study cited by the American Heartworm Society found that one-quarter of feline heartworm cases occurred in indoor cats.
Reported by the Companion Animal Parasite Council (CAPC) as treated for heartworm infection in the United States.
Contribute to CAPC's parasite prevalence data and annual forecasts.
Vectors do not stop at the door.
The U.S. Food and Drug Administration specifically notes that mosquitoes enter homes through open doors and windows, so cats and ferrets that rarely or never go outside still need a heartworm-prevention discussion.
A boundary is not a parasite barrier.
Fences help reduce roaming and hunting, but mosquitoes fly across them. Rodents and other wildlife may carry fleas and ticks into landscaped areas, while parasite eggs can persist where contaminated feces has been deposited.
Your neighborhood is still an ecosystem.
Climate, wildlife, transported pets, and changing vector ranges make risk local and dynamic. A pet does not need to visit a dog park or travel out of town to encounter a mosquito, flea, tick, or contaminated soil.
THE BOTTOM LINE
Lifestyle should shape the prevention plan—not decide whether one exists. The Companion Animal Parasite Council recommends year-round broad-spectrum parasite control for every dog and cat, tailored with a veterinarian to the pet’s health, species, age, geography, and actual exposure.
Statistics describe populations, not an individual pet’s exact odds. Prevalence varies by place, season, testing practices, preventive use, and travel history.
UNDERSTAND THE PARASITE
Protection makes more sense when you know what is being prevented.
Common names hide important differences in host range, life cycle, testing and treatment. These owner guides explain what may live on the animal, what develops in the home or yard, and why one negative test or one product may not answer every question.
FLEAS
Cat, dog and human fleas
Three named species, one shared household problem—and why the cat flea is usually the main culprit.
Read the flea guide →TICKSSix important tick species
Identification clues, disease associations, safe removal and matching prevention to the label.
Read the tick guide →MITESSarcoptic, Demodex and ear mites
Contagious versus normally resident mites, diagnostic tests and why treatment differs.
Read the mite guide →INTERNAL PARASITESWorms, protozoa and fecal testing
Roundworms, hookworms, whipworms, tapeworms, Giardia, coccidia and other causes.
Read the intestinal guide →About the tick listings: Species shown are United States label claims reviewed August 16, 2026. Claims can differ by animal species, formulation, dose interval and package revision. Always use the current package insert and your veterinarian’s recommendation.
COMPARISON FINDER
Start with what your pet needs.
32 matching products
Dog · Zoetis
PrescriptionSimparica Trio
sarolaner · moxidectin · pyrantel
FDA-approved animal drug
FleasTicksHeartwormRoundwormsHookworms
Labeled tick species: Lone star, Gulf Coast, American dog, black-legged/deer, brown dog and Asian longhorned ticks.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 8 weeks; 2.8 lb
Lyme-prevention claim through killing black-legged ticks; tapeworm claim is flea-vector specific.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Boehringer Ingelheim
PrescriptionNexGard Plus
afoxolaner · moxidectin · pyrantel
FDA-approved animal drug
FleasTicksHeartwormRoundwormsHookworms
Labeled tick species: Lone star, American dog, black-legged/deer, brown dog and Asian longhorned ticks.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 8 weeks; 4 lb
Broad monthly oral option. Test for heartworm infection before starting.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Elanco
PrescriptionCredelio Quattro
lotilaner · moxidectin · praziquantel · pyrantel
FDA-approved animal drug
FleasTicksHeartwormRoundwormsHookwormsTapeworms
Labeled tick species: Lone star, American dog, black-legged/deer, brown dog and Asian longhorned ticks.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 8 weeks; 3.3 lb
Includes three intestinal-worm groups. Give with food; test for heartworm before starting.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Elanco
PrescriptionTrifexis
spinosad · milbemycin oxime
FDA-approved animal drug
FleasHeartwormRoundwormsHookwormsWhipworms
- Form
- Tablet
- Frequency
- Monthly
- Minimum
- 8 weeks; 5 lb
No tick coverage. Give with food; review ivermectin use with your veterinarian.
Dog · Merck Animal Health
PrescriptionSentinel Spectrum
milbemycin oxime · lufenuron · praziquantel
FDA-approved animal drug
HeartwormRoundwormsHookwormsWhipwormsTapewormsFlea eggs
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 6 weeks; 2 lb
Prevents flea development but does not kill adult fleas.
Dog · Elanco
PrescriptionInterceptor Plus
milbemycin oxime · praziquantel
FDA-approved animal drug
HeartwormRoundwormsHookwormsWhipwormsTapeworms
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 6 weeks; 2 lb
Broad intestinal-worm option without flea or tick control.
Dog · Boehringer Ingelheim
PrescriptionHeartgard Plus
ivermectin · pyrantel
FDA-approved animal drug
HeartwormRoundwormsHookworms
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 6 weeks
No flea or tick coverage. Heartworm testing is required as directed by a veterinarian.
Dog · Merck Animal Health
PrescriptionTri-Heart Plus
ivermectin · pyrantel
FDA-approved animal drug
HeartwormRoundwormsHookworms
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 6 weeks
No flea or tick coverage; an ivermectin/pyrantel alternative.
Dog · Zoetis
PrescriptionProHeart 6
moxidectin
FDA-approved animal drug
HeartwormHookworms
- Form
- Injection
- Frequency
- Every 6 months
- Minimum
- 6 months
Veterinarian-administered. Not for sick, debilitated, or underweight dogs.
Dog · Zoetis
PrescriptionProHeart 12
moxidectin
FDA-approved animal drug
HeartwormHookworms
- Form
- Injection
- Frequency
- Yearly
- Minimum
- 12 months
Veterinarian-administered yearly heartworm prevention; no flea or tick coverage.
Dog · Merck Animal Health
PrescriptionBravecto Quantum
fluralaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Black-legged/deer, American dog, brown dog, Gulf Coast and Asian longhorned ticks for 12 months; lone star tick for 8 months.
- Form
- Injection
- Frequency
- Yearly
- Minimum
- 6 months
Veterinarian-administered; most ticks covered for 12 months, lone star tick for 8 months.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Merck Animal Health
PrescriptionBravecto Chew
fluralaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Black-legged/deer, American dog and brown dog ticks for 12 weeks; lone star tick for 8 weeks.
- Form
- Chew
- Frequency
- Every 12 weeks
- Minimum
- 6 months
Lone star tick claim is 8 weeks; other labeled tick claims extend to 12 weeks.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Merck Animal Health
PrescriptionBravecto 1-Month
fluralaner
FDA-approved animal drug
FleasTicks
Labeled tick species: See the current package insert for the tick species and age-specific claim; the one-month puppy formulation does not inherit every claim from other Bravecto formulations.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 8 weeks
Lone star tick use is for dogs 6 months and older.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Boehringer Ingelheim
PrescriptionNexGard
afoxolaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Lone star, American dog, black-legged/deer, brown dog and Asian longhorned ticks.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 8 weeks; 4 lb
Monthly oral flea/tick control; no heartworm coverage.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Zoetis
PrescriptionSimparica
sarolaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Lone star, Gulf Coast, American dog, black-legged/deer, brown dog and Asian longhorned ticks.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 6 months; 2.8 lb
Monthly oral flea/tick control; no heartworm coverage.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog · Elanco
PrescriptionCredelio
lotilaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Lone star, American dog, black-legged/deer, brown dog and Asian longhorned ticks.
- Form
- Chew
- Frequency
- Monthly
- Minimum
- 8 weeks; 4.4 lb
Give with food for reliable absorption.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog + Cat · Zoetis
PrescriptionRevolution
selamectin
FDA-approved animal drug
FleasHeartwormEar mitesSarcoptic mange
- Form
- Topical
- Frequency
- Monthly
- Minimum
- Dogs 6 wk; cats 8 wk
Coverage differs by species; the cat label includes roundworms and hookworms.
Dog + Cat · Elanco
PrescriptionAdvantage Multi
imidacloprid · moxidectin
FDA-approved animal drug
FleasHeartwormRoundwormsHookwormsWhipwormsEar mites
- Form
- Topical
- Frequency
- Monthly
- Minimum
- Dogs 7 wk/3 lb; cats 9 wk/2 lb
Species-specific labels: whipworm is canine; ear-mite coverage is feline.
Dog · Elanco
Over-the-counterK9 Advantix II
imidacloprid · permethrin · pyriproxyfen
EPA-registered pesticide
FleasTicksMosquitoesLiceBiting flies
Labeled tick species: Lone star, American dog, black-legged/deer and brown dog ticks; dog-only permethrin product.
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 7 weeks
DOGS ONLY. Permethrin can be dangerously toxic to cats.
Dog + Cat · Boehringer Ingelheim
Over-the-counterFrontline Plus
fipronil · (S)-methoprene
EPA-registered pesticide
FleasTicksLiceFlea eggs
Labeled tick species: Dog and cat labels differ; labeled species include American dog, brown dog, lone star and black-legged/deer ticks. Verify the species-specific package.
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks
Use the species-specific package; follow label bathing directions.
Dog + Cat · Boehringer Ingelheim
Over-the-counterFrontline Gold
fipronil · (S)-methoprene · pyriproxyfen
EPA-registered pesticide
FleasTicksLiceFlea eggs
Labeled tick species: Dog and cat labels differ; labeled species include American dog, brown dog, lone star and black-legged/deer ticks. Verify the species-specific package.
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks
Three ingredients target adult fleas and immature stages.
Dog + Cat · Elanco
Over-the-counterSeresto
imidacloprid · flumethrin
EPA-registered pesticide
FleasTicksLice
Labeled tick species: Tick claims differ between dog and cat collars; verify the correct package for black-legged/deer, American dog, brown dog and lone star tick claims.
- Form
- Collar
- Frequency
- Up to 8 months
- Minimum
- 7 weeks
Continuous-wear collar. Follow fit and handling directions; use an authorized source.
Dog + Cat · Elanco
Over-the-counterAdvantage II
imidacloprid · pyriproxyfen
EPA-registered pesticide
FleasFlea eggsLice
- Form
- Topical
- Frequency
- Monthly
- Minimum
- Dogs 7 wk; cats 8 wk
No tick or heartworm coverage. Use the correct species and weight package.
Dog + Cat · Elanco
Over-the-counterCapstar
nitenpyram
FDA-approved animal drug
Fleas
- Form
- Tablet
- Frequency
- 24-hour action
- Minimum
- 4 weeks; 2 lb
Rapid adult-flea kill, not month-long prevention; typically one part of a control plan.
Dog · Ceva
Over-the-counterVectra 3D
dinotefuran · permethrin · pyriproxyfen
EPA-registered pesticide
FleasTicksMosquitoesLiceBiting flies
Labeled tick species: Lone star, Gulf Coast, American dog, black-legged/deer and brown dog ticks; dogs only.
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks
DOGS ONLY. Do not use on cats; prevent feline contact until dry.
Cat · Boehringer Ingelheim
PrescriptionNexGard Combo
esafoxolaner · eprinomectin · praziquantel
FDA-approved animal drug
FleasTicksHeartwormRoundwormsHookwormsTapewormsEar mites
Labeled tick species: Cats: black-legged/deer and lone star ticks.
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks; 1.8 lb
Broad feline topical covering ectoparasites, heartworm, nematodes, and tapeworms.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Cat · Zoetis
PrescriptionRevolution Plus
selamectin · sarolaner
FDA-approved animal drug
FleasTicksHeartwormRoundwormsHookwormsEar mites
Labeled tick species: Cats: black-legged/deer, Gulf Coast and American dog ticks.
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks; 2.8 lb
Labeled for cats regardless of heartworm status.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Cat · Merck Animal Health
PrescriptionBravecto Plus
fluralaner · moxidectin
FDA-approved animal drug
FleasTicksHeartwormRoundwormsHookworms
Labeled tick species: Cats: black-legged/deer ticks; duration differs from flea and heartworm claims.
- Form
- Topical
- Frequency
- Every 2 months
- Minimum
- 6 months; 2.6 lb
Two-month feline combination. Use caution in heartworm-positive cats.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Cat · Merck Animal Health
PrescriptionBravecto Topical
fluralaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Cats: black-legged/deer ticks; confirm the current package insert for duration.
- Form
- Topical
- Frequency
- Every 12 weeks
- Minimum
- 6 months; 2.6 lb
Long-duration flea/tick topical; no heartworm protection.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Cat · Elanco
PrescriptionCredelio CAT
lotilaner
FDA-approved animal drug
FleasTicks
Labeled tick species: Cats: black-legged/deer ticks.
- Form
- Tablet
- Frequency
- Monthly
- Minimum
- 6 months; 2 lb
Oral feline flea/tick option. Administer with food.
◆ Isoxazoline class—review neurologic history with your veterinarian.
Dog + Cat · PetArmor
Over-the-counterPetArmor Plus
fipronil · (S)-methoprene
EPA-registered pesticide
FleasTicksLiceFlea eggs
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks; use the species- and weight-specific package
EPA-registered topical sold in separate dog and cat packages. Label claims and minimum weights differ by package.
Cat · Elanco
Over-the-counterCheristin
spinetoram
EPA-registered pesticide
Fleas
- Form
- Topical
- Frequency
- Monthly
- Minimum
- 8 weeks; 1.8 lb
Cats only; adult flea control without tick or heartworm coverage.
READ BEFORE CHOOSING
Coverage is only the first filter.
Registered and approved are different pathways.
FDA-approved animal drug means the Food and Drug Administration reviewed the animal drug under its approval standards. EPA-registered pesticide means the Environmental Protection Agency registered the pesticide after reviewing label claims and risks under pesticide law. Neither badge means “best” for an individual pet.
How to identify the regulator on the label ↗Heartworm testing matters
Dogs should be tested according to veterinary guidance before starting or changing prevention. Prevention does not treat adult heartworms.
Isoxazoline caution
The U.S. Food and Drug Administration (FDA) notes possible neurologic adverse events—including tremors, ataxia, and seizures—in some pets receiving isoxazolines.
FDA fact sheet ↗Cats + permethrin do not mix
Never apply a dog-only permethrin product to a cat. Prevent contact with a treated dog until the label-directed drying period is complete.
Labels beat assumptions
Age, weight, tick species, duration, bathing rules, and breeding safety can differ—even within one brand family.
ABOUT THIS REFERENCE
Built for comparison,
not prescribing.
This directory focuses on major branded U.S. products and common over-the-counter standards. It does not list every private-label generic, regional product, spray, shampoo, or environmental pesticide. Product availability and labels change.
Coverage is simplified to major parasite groups; it does not imply every species or life stage. Your veterinarian should make the final recommendation using geography, lifestyle, health history, medications, and testing.
Last reviewed: August 15, 2026 · Always confirm the current package insert.