NexGard Spectra

Description

Your Dog Deserves Better Than Five Different Products

Ask any dog owner about their parasite prevention routine and you'll often hear the same thing — a flea treatment applied to the back of the neck, a separate heartworm pill given at a different time, maybe a tick collar on top of it all, and then a dewormer the vet mentioned during the last visit that somehow got lost in the shuffle.

It works, in theory. In practice, it's a lot to keep track of. And gaps happen — a dose gets forgotten, the collar expires without being replaced, or the flea treatment was applied but the heartworm preventive wasn't given that month.

NexGard Spectra for dogs solves this by replacing all of that with a single monthly chew. One tablet, once a month, covering fleas, three tick species, heartworm, roundworms, hookworms, whipworms, demodectic mange, and Lyme disease risk reduction. Your dog will likely eat it straight from your hand — it's beef-flavoured and soft enough that most dogs treat it like a reward rather than a medication.

Manufactured by Boehringer Ingelheim and available across Canada by veterinary prescription, NexGard Spectra is one of the most comprehensive oral parasite preventives available for dogs today.

The Full Protection List — What NexGard Spectra Covers

Fleas: NexGard Spectra kills adult fleas (Ctenocephalides felis) within 6 to 8 hours of the first dose. It eliminates them before they can lay eggs, breaking the flea life cycle and preventing re-infestation. With monthly use, all developmental stages of fleas — eggs, larvae, and adults — are progressively eliminated from your dog's environment.

Ticks — Three Species Covered in Canada:

• American Dog Tick (Dermacentor variabilis) — over 90% killed within 48 hours
• Black-Legged Tick / Deer Tick (Ixodes scapularis) — over 90% killed within 48 hours; carrier of Lyme disease
• Lone Star Tick (Amblyomma americanum) — over 90% killed within 72 hours

Lyme Disease Risk Reduction: By killing black-legged ticks before they can complete their feeding cycle, NexGard Spectra reduces Borrelia burgdorferi infection risk — the bacteria responsible for Lyme disease in dogs and people.

Heartworm Disease Prevention: NexGard Spectra prevents heartworm disease (Dirofilaria immitis) when given monthly. Mosquitoes transmit heartworm larvae when they bite — the milbemycin oxime in each tablet stops those larvae from developing into the dangerous adult worms that migrate to the heart and lungs.

Intestinal Worms — Three Types Treated and Controlled:

• Roundworms (Toxocara canis, Toxascaris leonina)
• Hookworms (Ancylostoma caninum)
• Whipworms (Trichuris vulpis)

Demodicosis: NexGard Spectra treats demodicosis caused by Demodex canis — a skin mite condition that causes hair loss, redness, and skin lesions. With regular monthly use, parasite load is reduced and lesions can heal completely.

How NexGard Spectra Works — Two Ingredients, Two Targets

Most parasite problems fall into one of two categories: external parasites living on the skin (fleas, ticks, mites) and internal parasites living inside the body (heartworm larvae, intestinal worms). NexGard Spectra handles both simultaneously through two active ingredients that each work on a different target.

Afoxolaner — Targeting External Parasites

Afoxolaner is an isoxazoline-class ectoparasiticide that's absorbed into the bloodstream after your dog chews the tablet. It distributes through the body's tissues and blood. When fleas, ticks, or mites bite and start feeding, they ingest afoxolaner along with the blood.

Inside the parasite, afoxolaner blocks specific chloride ion channels in the nervous system — channels that are unique to invertebrates and are not present in dogs or people. Without these channels functioning, the parasite's nervous system goes into overdrive. Uncontrolled neurological hyperexcitation causes rapid paralysis and death.

The specificity of this target is what makes afoxolaner both effective against parasites and safe for dogs.

Milbemycin Oxime — Targeting Internal Parasites

Milbemycin oxime is a macrocyclic lactone endoparasiticide that works differently from afoxolaner. In the gut, it targets glutamate-gated chloride channels in invertebrate nerve and muscle cells — channels that are essential for normal neuromuscular function in worms and heartworm larvae.

By binding to these channels, milbemycin oxime increases chloride ion flow into the cells, causing hyperpolarization of the neuromuscular membrane. The worms become paralyzed, lose their grip in the intestine, and are expelled naturally in your dog's stool. Against heartworm larvae specifically, it prevents the L3 and L4 larval stages from developing further — stopping the parasite long before it can reach the heart.

Together, afoxolaner and milbemycin oxime cover the complete spectrum of common canine parasites — internal and external — in a single oral dose.

NexGard Spectra Canada — Dosage, Sizing, and How to Give It

Dose: One chewable tablet, once every 30 days. Can be given with or without food — this is one practical advantage NexGard Spectra has over some alternatives that require administration with a meal.

Finding the right size: Always dose by actual body weight. Weigh your dog before ordering.

How to give it: Most dogs will take NexGard Spectra directly from your hand — the beef flavour and soft texture make it palatable enough that few dogs resist. If yours is picky, offer it with a small amount of food. Watch your dog for a few minutes after giving the dose to confirm the entire tablet was eaten and not quietly dropped somewhere on the floor.

If vomiting occurs within 2 hours of dosing, contact your vet — the dose may not have been absorbed and a replacement may be needed.

Starting NexGard Spectra: You can begin at any time of year. For heartworm prevention, start one month before your dog's first seasonal mosquito exposure and continue until one month after the last seasonal exposure. Year-round dosing is recommended across most of Canada. If switching from another monthly heartworm preventive, give the first NexGard Spectra dose within one month of the last dose of the previous product.

Missed dose: Give it as soon as you notice and then resume the monthly schedule from that new date.

NexGard Spectra Side Effects — What to Watch For

NexGard Spectra is well tolerated by most dogs. Side effects occur in a small percentage of patients and are typically mild.

Most commonly reported:

• Vomiting
• Diarrhea
• Decreased appetite (anorexia)
• Lethargy
• Hyperactivity
• Skin reactions — itching (pruritus) or skin irritation

These generally resolve on their own without treatment. If they persist or worsen, contact your vet.

Serious side effects — contact your veterinarian immediately:

Neurological reactions — NexGard Spectra contains afoxolaner, an isoxazoline-class parasiticide. This drug class carries an FDA and Health Canada label warning regarding the potential for neurological adverse reactions including:

• Tremors or muscle twitching
• Uncoordinated movement (ataxia)
• Seizures

These reactions are uncommon but have been documented, most often in dogs with a pre-existing history of seizures or neurological disorders. If your dog has ever had a seizure, this must be disclosed to your vet before starting NexGard Spectra.

Signs of allergic reaction — facial swelling, hives, difficulty breathing, sudden collapse — seek emergency veterinary care immediately.

Who Should Not Take NexGard Spectra

Do not give NexGard Spectra if your dog:

• Has a known allergy to afoxolaner, milbemycin oxime, or any ingredient in the tablet
• Is under 8 weeks of age
• Weighs less than 2 kg
• Is a cat — for dogs only; do not give to cats

Use with caution and explicit veterinary guidance if:

• Your dog has a history of seizures or epilepsy — isoxazolines can lower the seizure threshold
• Your dog is pregnant, breeding, or lactating — safety in these dogs has not been established; use only when the benefit clearly outweighs the risk, as determined by your vet
• Your dog already has heartworm disease — NexGard Spectra is a preventive; it does not treat adult heartworm infections. Dogs in endemic areas should be tested before starting any heartworm preventive

Important for humans: Wash hands after administering. This product is not for human use. If accidental ingestion occurs, seek medical advice and bring the product label.

NexGard Spectra in Canada — Parasite Risks Worth Knowing

Canadian dog owners face a specific and evolving parasite landscape that makes broad-spectrum protection genuinely worthwhile:

Ticks and Lyme Disease: Black-legged ticks are well established in southern Ontario, parts of Quebec, Nova Scotia, New Brunswick, and Manitoba, with their range expanding northward every year. NexGard Spectra kills black-legged ticks and reduces Lyme disease transmission risk — relevant for any dog with outdoor exposure in these regions.

Heartworm: Heartworm is no longer just a concern in the southern United States. Its range has moved significantly into Canada, with documented cases in Ontario, Quebec, Manitoba, and British Columbia. The Canadian Parasitology Expert Panel (CPEP) recommends year-round or extended heartworm prevention for most Canadian dogs. Monthly preventives like NexGard Spectra are the standard approach.

Intestinal Worms: Roundworms and whipworms are common across Canada — particularly in puppies, rescue dogs, and dogs with outdoor exposure. NexGard Spectra treats all three major intestinal worm types, which makes it one of the more complete options for dogs at risk of intestinal parasite exposure.

Storage

• Store at room temperature between 15°C and 30°C
• Keep away from heat, direct sunlight, and moisture
• Keep in original packaging until use
• Store out of reach of children and other animals
• For dogs only — keep away from cats
• Do not use past the printed expiry date