Medication Guide • Reviewed by Dr. Tiffany Delacruz, DVM
Interceptor Plus for Dogs
Interceptor Plus is a monthly flavored chewable that prevents heartworm and controls all five common intestinal worms in dogs — including tapeworm, which most heartworm preventives don't cover.
What Interceptor Plus is used for in dogs
- Monthly heartworm prevention
- Roundworm, hookworm, whipworm, AND tapeworm control
How it works
Milbemycin oxime kills heartworm larvae and intestinal nematodes; praziquantel paralyzes and kills tapeworms.
Available formulations
Chicken-flavored chewable in multiple weight ranges, monthly
Side effects to know
Common side effects
- • Vomiting (rare)
- • Decreased appetite (rare)
These usually resolve on their own. If they persist past the first few doses, ask your vet.
Call your vet immediately if you see
- ⚠ Neurologic signs in MDR1 breeds at high doses (rare at preventive dose)
Drug interactions
- • Generally well-tolerated
When not to use
- • Heartworm-positive dogs (test first)
- • Puppies under 6 weeks or 2 lbs
Monitoring during treatment
Annual heartworm test before refill.
Need a Interceptor Plus refill?
RexVet is the first 501(c)(3) non-profit online vet service in the U.S. Talk to a licensed veterinarian by video, get your dogs's Interceptor Plus prescription, and have it shipped through RexVetRx — all for $64.99 per visit.
Book a vet visit — $64.99Interceptor Plus for Dogs
Frequently asked questions
Interceptor Plus vs Heartgard Plus?
Both prevent heartworm and roundworms/hookworms. Interceptor Plus adds whipworm and tapeworm coverage. Many vets prefer it for dogs at risk of tapeworm exposure (e.g. flea-prone or rodent-hunting dogs).
Does my dog need tapeworm coverage?
Yes if your dog has fleas (tapeworm comes from swallowing infected fleas) or hunts rodents. Many monthly heartworm preventives skip tapeworm; Interceptor Plus includes it.
Is Interceptor Plus safe for Collies?
Yes at the preventive dose. The MDR1 concern relates to high doses of ivermectin or milbemycin used for other parasites — not the small preventive dose in Interceptor Plus.
Can RexVet prescribe Interceptor Plus?
Yes — with a current negative heartworm test, RexVet ships through RexVetRx.
Does Interceptor Plus cover fleas or ticks?
No — it's heartworm + intestinal worms only. For fleas/ticks you need a separate product or a combination like Trifexis (fleas) or Simparica TRIO (fleas + ticks).
Medical review by Dr. Tiffany Delacruz, DVM
Chief Executive Officer & Lead Veterinarian, RexVet. Licensed in Florida, New York, and Virginia.
Last fact-checked: 2026-05-19
Sources
This page is an educational reference and does not replace veterinary advice. Always consult a licensed veterinarian before starting, changing, or stopping medication for your pet.