NexGard Spectra vs Simparica Trio: NZ Vet's Guide to All-in-One Protection

Quick answer

Both NexGard Spectra and Simparica Trio are monthly all-in-one chews that cover fleas, ticks, and intestinal worms in a single dose. The main differences: NexGard Spectra also covers heartworm, while Simparica Trio covers heartworm plus has a slightly broader mite claim. Pricing in NZ is similar. For most Kiwi dog owners, either product is an excellent choice — your vet’s preference and your dog’s history will likely be the deciding factor.

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Why this comparison matters in NZ

If you search this comparison today, every result is either Australian or international. Nothing accounts for NZ parasite conditions, NZ pricing, or NZ availability. And these are expensive, recurring purchases — owners deserve NZ-specific information before committing to a monthly treatment plan.

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What each product covers

NexGard Spectra (Boehringer Ingelheim)

• Active ingredients: Afoxolaner + Milbemycin oxime
• Fleas: ✅ Kills adult fleas within 8 hours
• Ticks: ✅ Paralysis ticks, brown dog ticks, bush ticks
• Heartworm: ✅ Prevention
• Roundworm: ✅
• Hookworm: ✅
• Whipworm: ✅
• Mites: Partial — demodex (some label claims vary by region)
• Tapeworm: ❌ Not covered

Simparica Trio (Zoetis)

• Active ingredients: Sarolaner + Moxidectin + Pyrantel
• Fleas: ✅ Kills adult fleas within 4 hours
• Ticks: ✅ Paralysis ticks, brown dog ticks, bush ticks, lone star ticks
• Heartworm: ✅ Prevention
• Roundworm: ✅
• Hookworm: ✅
• Whipworm: ❌ Not covered
• Mites: ✅ Demodex and sarcoptes (broader mite claim)
• Tapeworm: ❌ Not covered

Key differences at a glance

Feature	NexGard Spectra	Simparica Trio
Flea kill speed	8 hours	4 hours
Whipworm	✅	❌
Mite coverage	Partial	Broader
Tick species range	Standard NZ ticks	Slightly broader
Minimum age	8 weeks, 2 kg	8 weeks, 1.25 kg
Dosing	Monthly chew	Monthly chew

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NZ pricing comparison

Approximate NZ pricing for a medium dog (10–20 kg), March 2026:

• NexGard Spectra (1 chew): $25–35
• NexGard Spectra (3-pack): $65–85
• NexGard Spectra (6-pack): $120–155
• Simparica Trio (1 chew): $24–34
• Simparica Trio (3-pack): $60–80
• Simparica Trio (6-pack): $110–145

Monthly cost is very similar between the two — typically within $1–3 of each other for the same weight range. Buying in 6-packs saves around 15–20% compared to single-chew pricing.

Where to buy in NZ: veterinary clinics, PetDirect (prescription section), VetPost, Pet Chemist NZ. Both require a veterinary prescription.

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NZ parasite context

New Zealand’s parasite landscape is different from Australia’s, and that matters for this comparison:

What NZ dogs actually face

• Fleas — present year-round, worst November–March. Both products handle this equally well
• Ticks — brown dog ticks and bush ticks are present but far less common than in Australia. NZ does not have paralysis ticks (that’s an Australian problem)
• Heartworm — rare in NZ but not non-existent. The NZ Veterinary Association still recommends prevention, particularly in warmer northern regions
• Intestinal worms — roundworm, hookworm, and whipworm are all present in NZ. Whipworm is less common but still a consideration
• Mites — demodex and sarcoptic mange occur in NZ dogs

What this means for your choice

The practical differences between these products matter less in NZ than in, say, tropical Queensland. NZ’s parasite burden is relatively moderate. The biggest factors for most NZ owners will be price, vet recommendation, and whether your dog has specific issues (mites, whipworm history).

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Which should you choose?

Choose NexGard Spectra if:

• Your vet recommends it (and many NZ vets default to NexGard)
• You want whipworm coverage — NexGard Spectra covers whipworm, Simparica Trio doesn’t
• You’re already using NexGard for fleas and ticks and want to step up to all-in-one without changing drug families
• Your dog has done well on NexGard products previously

Choose Simparica Trio if:

• You want faster flea kill — Simparica Trio claims flea kill within 4 hours vs NexGard Spectra’s 8 hours
• Your dog has mite issues — Simparica Trio has a broader mite label claim
• You have a very small puppy — Simparica Trio can be used from 1.25 kg (vs NexGard Spectra’s 2 kg minimum)
• Your vet recommends the Zoetis product line
• You want the slightly cheaper option — pricing is marginally lower in most weight ranges

Either product works well if:

• You want simple, one-chew monthly protection
• Your dog is healthy with no specific parasite history
• You’re in an urban or suburban NZ area with typical parasite exposure

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What neither product covers

Both NexGard Spectra and Simparica Trio leave gaps:

• Tapeworm — neither covers tapeworm. If your dog hunts rabbits, eats raw offal, or has had tapeworm before, you’ll need a separate tapeworm treatment (typically praziquantel, available as Drontal or similar)
• Hydatid tapeworm — particularly relevant for NZ farm dogs. Requires specific treatment
• Lungworm — not covered by either product in NZ formulations

If your dog needs tapeworm coverage, ask your vet about adding a standalone wormer on a quarterly basis.

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Safety and side effects

Both products are in the isoxazoline drug class and have similar safety profiles:

• Common side effects: Vomiting, diarrhoea, lethargy (usually mild and temporary)
• Rare side effects: Tremors, ataxia (uncoordinated movement), seizures — reported in a small number of dogs across all isoxazoline products
• Dogs with seizure history: Discuss with your vet. Both products carry warnings for dogs with a history of seizures

Both are well-studied with millions of doses administered globally. Serious adverse reactions are rare but not zero. If your dog has never used an isoxazoline product before, monitor them after the first dose.

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Can you switch between them?

Yes. There’s no medical issue with switching from NexGard Spectra to Simparica Trio or vice versa. Allow the previous month’s dose to wear off before starting the new product. Consult your vet if your dog is on other medications.

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What about Bravecto?

Bravecto is a popular alternative that lasts 3 months per chew — but it only covers fleas and ticks, not worms or heartworm. If you want all-in-one protection, NexGard Spectra or Simparica Trio are the right comparison. If you only need flea and tick coverage, Bravecto may be better value.

Related: Bravecto vs NexGard in NZ

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Bottom line

For most NZ dog owners, the choice between NexGard Spectra and Simparica Trio comes down to your vet’s recommendation and minor practical differences:

• NexGard Spectra wins on whipworm coverage and brand familiarity
• Simparica Trio wins on flea kill speed, mite coverage, and slightly lower weight minimum
• Both are excellent all-in-one monthly chews that simplify your dog’s parasite protection

The wrong answer is not treating at all. Either of these products, given consistently every month, will protect your dog against the parasites that matter in New Zealand.

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Prices and availability checked March 2026. Both products require a veterinary prescription in New Zealand. Always consult your vet before starting or switching parasite treatments.