NexGard Plus Review (2026): Fleas, Ticks, Heartworm — One Chew

Affiliate disclosure: ReviewPooch earns commission on purchases made through links in this article, at no cost to you.

What NexGard Plus actually covers

NexGard Plus is Boehringer Ingelheim's all-in-one monthly chewable for dogs. Where the original NexGard only covers fleas and ticks, the Plus formulation adds heartworm prevention and intestinal worm treatment in the same tablet. One chew per month handles five parasite categories:

• Fleas — kills adult fleas, prevents flea infestations
• Ticks — black-legged tick, American dog tick, brown dog tick, lone star tick
• Heartworm — prevents Dirofilaria immitis infection (98.1% efficacy in controlled studies)
• Roundworms — treats and controls Toxocara canis and Toxascaris leonina
• Hookworms — treats and controls Ancylostoma caninum and Uncinaria stenocephala

For dogs who need heartworm prevention anyway — which is every dog in the US — NexGard Plus frequently replaces two separate monthly medications with one.

How the three active ingredients work

Afoxolaner (isoxazoline): The same molecule in original NexGard. Absorbed into your dog's bloodstream after the chew. Fleas and ticks bite, ingest afoxolaner, and die through overstimulation of their nervous systems. Kills fleas within 4-8 hours. Tick kill within 24-48 hours.

Moxidectin (macrocyclic lactone): An endectocide that interferes with chloride channel-mediated neurotransmission in parasites, causing paralysis and death. The same drug class used in Advantage Multi and Proheart injections. At the 12 mcg/kg monthly dose in NexGard Plus, moxidectin reliably prevents heartworm larval development.

Pyrantel pamoate (tetrahydropyrimidine): A depolarizing neuromuscular-blocking agent — it paralyzes intestinal roundworms and hookworms, which are then expelled from the GI tract. Pyrantel targets adult worms in the gut; moxidectin handles tissue-stage larvae and heartworm prevention.

⚠️ The safety warning

Afoxolaner is an isoxazoline — the drug class covered by the FDA's 2018 isoxazoline safety advisory. The required label language: "Use with caution in animals with a history of neurologic disorders such as epilepsy."

For healthy dogs with no seizure history, neurologic adverse reactions are documented but uncommon. For dogs with epilepsy or known neurological conditions, the conversation belongs with your vet before any isoxazoline product.

NexGard Plus vs the competition

vs NexGard (original): Same afoxolaner core. NexGard Plus adds moxidectin (heartworm) and pyrantel (roundworms/hookworms). If your dog already takes a monthly heartworm preventative like Heartgard Plus, switching to NexGard Plus replaces both tablets with one. For dogs who don't need heartworm coverage — none exist in the US, realistically — original NexGard is the lower-cost option.

vs Simparica Trio: The closest direct competitor. Both are monthly chewables combining an isoxazoline with moxidectin and pyrantel. Key differences: Simparica Trio uses sarolaner instead of afoxolaner, covers a fifth tick species (Amblyomma maculatum, the Gulf Coast tick), and is approved from 2.8 lbs vs NexGard Plus's 4 lb minimum. For dogs in Gulf Coast tick territory, this matters. For most of the US, NexGard Plus is comparably effective at a price point that is often lower at international pharmacies.

vs Heartgard Plus + NexGard (separate): This is what many US vets prescribe. Two monthly chews instead of one. More flexible dosing in some cases, but adds cost and one more medication to remember. NexGard Plus simplifies the regimen with no clinical trade-off for most dogs.

vs Bravecto: Bravecto (fluralaner) offers 12-week flea and tick protection in a single dose — fewer annual administrations, which is genuinely useful for owners who forget monthly dosing. But Bravecto doesn't cover heartworm or intestinal worms — you still need a monthly heartworm preventative alongside it. NexGard Plus as the complete monthly solution is often simpler and cheaper overall.

Efficacy data from clinical trials

Published data from Boehringer Ingelheim-sponsored and independent studies:

• Fleas: >98% reduction within 24 hours
• Ticks (Ixodes scapularis, Amblyomma americanum, Dermacentor variabilis, Rhipicephalus sanguineus): 92-100% within 48 hours
• Heartworm prevention: 98.1% against macrocyclic lactone-resistant D. immitis isolate in a 2026 Parasites & Vectors study
• Sarcoptic mange: 97% mite reduction after first treatment, 100% elimination after second (NexGard Plus is not labeled for mange, but moxidectin's antiparasitic activity extends to sarcoptic mange — discuss with your vet)

Dosing and weight classes

NexGard Plus comes in four color-coded weight ranges. All chews are beef-flavored.

• Green box: 4.4–8.0 lbs (2–4 kg)
• Green box (larger): 8.1–17.0 lbs (4–8 kg)
• Gold box: 17.1–33.0 lbs (8–15 kg)
• Red box: 33.1–66.0 lbs (15–30 kg)
• Blue box: 66.1–132.0 lbs (30–60 kg)

Minimum: 4 lbs body weight, 8 weeks of age. Give monthly, ideally on the same day each month.

What NexGard Plus costs — and where to save

At US veterinary clinics, NexGard Plus typically runs $20-30 per month depending on your dog's weight class, with a required vet consultation for the prescription. A 6-month supply plus annual wellness exam commonly totals $180-240 for the medication alone.

Canada Pet Care sources NexGard Plus from licensed international pharmacies where it's sold without the US prescription markup. The same Boehringer Ingelheim product for 30-45% less. Free shipping on orders over $49. For a medication your dog takes every month for life, the annual savings are substantial.

Frequently asked questions

Does NexGard Plus prevent Lyme disease?

NexGard Plus kills black-legged ticks (Ixodes scapularis) — the primary Lyme disease vector — within 48 hours. Since ticks typically require 36-48 hours of attachment to transmit Lyme, prompt tick kill substantially reduces transmission risk. It's not 100% protection, but it's meaningful. Regular tick checks after outdoor time remain important.

Can I use NexGard Plus if my dog already takes Heartgard Plus?

Switching from the Heartgard Plus + NexGard combination to NexGard Plus is exactly the scenario this product is designed for. Discontinue both, start NexGard Plus on the same monthly schedule. No tapering required. Confirm with your vet before switching, particularly if your dog has been on Heartgard during the same calendar month.

Does NexGard Plus work against all tick species in the US?

It covers four of the five primary species: black-legged tick, American dog tick, brown dog tick, and lone star tick. It does not cover the Gulf Coast tick (Amblyomma maculatum). If you're in Alabama, Georgia, Florida, or coastal Gulf states where Gulf Coast ticks are common, Simparica Trio's five-species coverage is worth considering.

My dog vomited after taking it. What should I do?

Give with food if you haven't been — this reduces GI upset significantly. If vomiting occurred within 1-2 hours of dosing, contact your vet about whether to redose. For most dogs, occasional vomiting resolves after the first few doses as they adjust to the new medication.

Is NexGard Plus the same as NexGard Spectra?

NexGard Plus (US market) and NexGard Spectra (sold in Europe, Australia, Canada) are closely related. NexGard Spectra additionally covers whipworms and tapes (via an additional active ingredient in some formulations). Canada Pet Care stocks both — your vet can advise on which formulation best fits your dog's parasite risk profile.

Ad — we may earn a commission at no extra cost to you.

Pros & Cons

Comparison Table

Related Reviews