⚡ Quick answer: NexGard Spectra (afoxolaner + milbemycin) dosage calculator. Color-coded monthly chewables: YELLOW/ORANGE/GREEN/PURPLE/RED by weight. Heartworm + fleas + ticks + intestinal worms.
NexGard Spectra for Dogs – All-in-One Monthly
NexGard Spectra combines afoxolaner + milbemycin oxime for monthly comprehensive parasite coverage. Primarily EU/UK/Australia (US has separate NexGard).
Chewable Sizing
| Weight | Color | Size |
|---|---|---|
| 2-3.5 kg | YELLOW | XS |
| 3.6-7.5 kg | ORANGE | S |
| 7.6-15 kg | GREEN | M |
| 15.1-30 kg | PURPLE | L |
| 30.1-60 kg | RED | XL |
| Over 60 kg | Combination | Multiple |
Coverage
| Parasite | Active |
|---|---|
| Heartworm | Milbemycin |
| Fleas (6-8h kill) | Afoxolaner |
| Ticks all species | Afoxolaner |
| Roundworms | Milbemycin |
| Hookworms | Milbemycin |
| Whipworms | Milbemycin |
| NOT tapeworms | Use Drontal Plus or Interceptor Plus |
| NOT sarcoptes/demodex | Use separate |
⚠ Isoxazoline FDA Warning
Afoxolaner (NexGard class):
- Rare muscle tremors
- Rare ataxia
- Rare seizures
- Caution in dogs with seizure history
MDR1 Safety
Milbemycin + afoxolaner at label doses SAFE for MDR1-mutant breeds.
Age + Weight
- From 8 weeks AND 2 kg
US Alternative
- NexGard (afoxolaner only – fleas/ticks)
- Plus monthly heartworm preventive (Heartgard, Interceptor Plus)
- Equivalent total coverage
When Tapeworms Needed
- Add Drontal Plus for single dose
- Or switch to Interceptor Plus (milbemycin + praziquantel)
Frequently Asked Questions
Which NexGard Spectra size for my dog?
Color-coded by weight: 1) 2-3.5 kg = YELLOW (XS); 2) 3.6-7.5 kg = ORANGE (S); 3) 7.6-15 kg = GREEN (M); 4) 15.1-30 kg = PURPLE (L); 5) 30.1-60 kg = RED (XL); 6) Over 60 kg = combine chewables
EXAMPLES:
- 5 kg Cavalier = ORANGE S
- 12 kg Beagle = GREEN M
- 25 kg Border Collie = PURPLE L
- 35 kg Lab = RED XL
- 65 kg Mastiff = combination
ADMINISTRATION: monthly with food preferred; beef-flavored. Available primarily EU/UK/Australia – US has separate NexGard + heartworm preventive
What does NexGard Spectra cover?
COMPREHENSIVE monthly parasite coverage:
- HEARTWORM prevention (milbemycin)
- FLEAS – killed within 6-8 hours (afoxolaner)
- TICKS – all major species including Lyme/Ehrlichia/Anaplasma vectors (afoxolaner)
- ROUNDWORMS Toxocara canis (milbemycin)
- HOOKWORMS Ancylostoma + Uncinaria (milbemycin)
- WHIPWORMS Trichuris vulpis (milbemycin)
NOT COVERED:
- Tapeworms (need Drontal Plus or Interceptor Plus)
- Sarcoptic mange (use Revolution or Advantage Multi)
- Demodex (use isoxazoline alone often works off-label)
- Ear mites
- Heartworm-positive dogs (vet supervision required). MDR1-safe at label dose for at-risk breeds (Collies, Aussies, Shelties, etc.)
Is NexGard Spectra available in the US?
NO – NexGard Spectra is primarily sold in EU, UK, Australia, NZ
US market has SEPARATE products:
- NEXGARD (afoxolaner only) – monthly chewable for fleas + ticks
- Plus monthly heartworm preventive needed: Heartgard Plus, Interceptor Plus, Revolution, Advantage Multi, etc
US ALTERNATIVES for ALL-IN-ONE:
- SIMPARICA TRIO (sarolaner + moxidectin + pyrantel) – heartworm + fleas + ticks + round/hook (no whip, no tape)
- REVOLUTION PLUS (selamectin + sarolaner) – topical comprehensive
- TRIFEXIS (spinosad + milbemycin) – heartworm + intestinal + fleas (no ticks). Discuss with US vet for appropriate product. Same active ingredients available in NexGard + Interceptor Plus combination = essentially equivalent to Spectra coverage
Related PuppaDogs Calculators
Continue building your dog’s personalised care plan with these related PuppaDogs calculators:
- Dog Pregnancy / Whelping Due-Date Calculator
- Puppy Weight Predictor (Adult Weight Calculator)
- Heatstroke Risk Calculator for Dogs
- Bloat (GDV) Risk Calculator for Dogs
- Dog Life Expectancy Calculator (Breed, Body Condition, Lifestyle)
- Spay/Neuter Timing Calculator for Dogs (Breed-Specific)
References & Further Reading
The dosing ranges and safety information on this page are drawn from the following veterinary references. Always defer to your own veterinarian and the manufacturer’s label for your specific product.
- NexGard Spectra product information – Boehringer Ingelheim.
- Plumb DC. Afoxolaner, milbemycin oxime.
- FDA Isoxazoline Class Warning.
- CAPC Parasite Control Guidelines.
- PuppaDogs. NexGard Calculator, Interceptor Plus Calculator. puppadogs.com.
⚕️ Medical disclaimer
The information on this page is intended for educational purposes only and does not replace a hands-on veterinary examination. Drug doses depend on your dog’s complete clinical picture, concurrent medications, and the exact product formulation. Always confirm dosing with your veterinarian before administering any medication, and contact a 24-hour veterinary emergency service or animal poison control immediately if you suspect a medication overdose or adverse reaction. PuppaDogs editorial standards: every drug dose published here is cross-checked against multiple authoritative veterinary references and reviewed by the PuppaDogs Veterinary Editorial Team before publication.
