
Frequently asked questions
My dog is between 16 and 18 lbs — should I use Yellow or Green?
At the upper boundary, size up. If your dog weighs 16.6 lbs or more, choose the Green pack (16.6–33 lbs). NexGard Spectra is dosed effectively at the low end of each band, so moving up doesn’t harm your dog — it just ensures full coverage.
Does Yellow cover heartworm, or do I need a separate preventative?
Yellow covers heartworm prevention. You don’t need a separate heartworm preventative — that’s the whole point of choosing NexGard Spectra over regular NexGard.
How is NexGard Spectra different from regular NexGard?
Regular NexGard covers fleas and ticks. NexGard Spectra adds heartworm prevention plus three common intestinal worms (roundworm, hookworm, whipworm) using a second active ingredient (milbemycin oxime). One chew, six parasites covered.
Can I switch from a topical to NexGard Spectra?
Yes — you can switch directly on your next dosing date. Give the NexGard Spectra chew on the day your topical would have been applied. No washout period needed.
Do I need a prescription to buy NexGard Spectra?
No — SmartWay Pet Supplies ships NexGard Spectra over the counter to customers across the US and Canada. No prescription or vet authorization required.
Should I dose year-round?
Yes — year-round dosing is recommended for both flea/tick control and continuous heartworm prevention. Mosquitoes (the heartworm vector) are active in most US/Canada regions for more of the year than people realize, and missing doses can leave dangerous gaps.