MoxiGuard Plus – Moxidectin, Pyrantel & Sarolaner Oral Solution

MoxiGuard Plus is a monthly liquid parasite preventive for dogs that combines moxidectin, sarolaner, and pyrantel in a single dose. Moxidectin works by disrupting nerve signaling in heartworm larvae, preventing them from developing into adult heartworms; sarolaner does something similar in fleas and ticks, causing uncontrolled nerve and muscle activity that kills them quickly; and pyrantel paralyzes the muscles of roundworms and hookworms in the gut so they’re expelled in the stool. Together, this gives a single monthly dose broad coverage against some of the most common parasites dogs face. Vetgrade.com’s MoxiGuard Plus is measured precisely each month with an oral syringe based on your dog’s current body weight.

Animals It’s Used For

Dogs. This formulation is not intended for cats, horses, livestock, birds, or other species — the ingredient combination and dosing here are calibrated specifically for canine use.

Symptoms & Indications

Heartworm Disease (Prevention, Not Treatment)

• Coughing, especially after exercise
• Reduced tolerance for activity or exercise
• Weight loss and reduced appetite in more advanced cases

MoxiGuard Plus prevents heartworm larvae from developing into adult heartworms — it does not treat dogs that already have adult heartworm infection. See the safety notes below on heartworm testing before starting.

Flea & Tick Infestation Symptoms

• Visible fleas, flea dirt, or ticks in the coat
• Scratching, biting, or licking at the skin
• Redness, hair loss, or scabbing from flea allergy dermatitis

Intestinal Worm Symptoms (Roundworms & Hookworms)

• Diarrhea or soft stool
• A pot-bellied appearance, especially in puppies
• Poor coat condition or slow growth
• Visible worms or worm segments in stool (roundworms in particular)
• Pale gums in heavy hookworm infestations, from blood loss

Important Safety Notes

Test for heartworm before starting. Dogs should be tested for existing heartworm infection before beginning MoxiGuard Plus. This product prevents new heartworm infections but doesn’t kill adult heartworms, and giving it to a dog that already has adult heartworms can cause a serious, even fatal, reaction as the worms die off in an uncontrolled way.

Moxidectin dose runs above the independently studied minimum at this concentration. Based on this formula’s fixed ratio of ingredients, the volume needed to correctly dose sarolaner and pyrantel delivers moxidectin at roughly 2.5 times its independently studied minimum effective dose. Moxidectin generally has a wide margin of safety, including in dogs with the MDR1 (ABCB1) drug-sensitivity mutation common in collies and related breeds, but this is still a meaningful deviation from the studied dose and worth discussing with your veterinarian, particularly for dogs with known drug sensitivities.

Isoxazoline class caution. Sarolaner belongs to the isoxazoline class, which the FDA has noted can occasionally cause neurologic side effects — muscle tremors, incoordination, or seizures — in some dogs, including dogs with no prior seizure history. Use with extra caution in dogs with a history of seizures or other neurologic conditions, and contact your veterinarian if these signs appear after dosing.

Not evaluated in breeding, pregnant, or nursing dogs. The safety of this ingredient combination hasn’t been established in these situations — talk to your veterinarian about alternatives if this applies to your dog.

Give monthly, without gaps. Missed or late monthly doses can leave a window of unprotected time against heartworm larvae and reduce overall effectiveness.

MoxiGuard Plus Dosing Chart

Doses below reflect commonly referenced veterinary ranges and are for general informational purposes. Always confirm exact dosing with a veterinarian, and see the safety note above regarding the moxidectin component.

Dosing Instructions

1. Shake the bottle thoroughly before each use to ensure a completely uniform solution.
2. Weigh your dog for accurate dosing — this matters more with a monthly preventive, since consistent accuracy over time is what maintains protection.
3. Using a calibrated oral syringe, measure the exact monthly dose for your dog’s current weight.
4. Administer directly into the mouth, or mix thoroughly into a small portion of wet food that will be consumed immediately.
5. Give on the same date each month to avoid gaps in heartworm protection.
6. Confirm a negative heartworm test before the first dose, and follow your veterinarian’s recommended retesting schedule going forward.
7. Watch for tremors, wobbliness, or unusual behavior in the hours after dosing, especially with the first dose, and contact your veterinarian if these appear.

FAQs

Can MoxiGuard Plus be used in pregnant or nursing dogs?
This hasn’t been evaluated for breeding, pregnant, or nursing dogs, so it’s generally not recommended in those situations. Talk to your veterinarian about safer alternatives if this applies to your dog.

Is there a withdrawal period I need to know about?
No — dogs aren’t food-producing animals, so a meat or milk withdrawal period doesn’t apply here. This question mostly comes up with livestock and poultry products; it isn’t relevant for a dog-only preventive like this one.

Why do I need a heartworm test before starting?
Because this product prevents new heartworm infections but doesn’t kill adult heartworms already present. Giving it to a dog that unknowingly already has adult heartworms can trigger a dangerous reaction as the worms die off, which is why a negative test first is a safety step, not just a formality.

My dog had tremors or seemed unsteady after dosing — is that expected?
No, and it should be reported to your veterinarian. Sarolaner, one of the three active ingredients, belongs to a drug class that can occasionally cause neurologic side effects like tremors, incoordination, or seizures in some dogs, even without a prior history. It’s uncommon, but it’s not something to wait out.

Does this treat fleas and ticks that are already on my dog, or just prevent new ones?
Both — it kills existing adult fleas and ticks in addition to helping prevent new infestations through the rest of the month. It’s not just a preventive-only product for those two parasites.

My puppy has a round belly and I see worms in the stool — will this treat that?
Yes, the pyrantel component treats and controls roundworms and hookworms, which commonly cause exactly those signs in puppies. That said, confirm the diagnosis and appropriate starting age with your veterinarian, since very young puppies may need a different deworming approach before transitioning to a monthly preventive.

What happens if I give a dose late?
Give it as soon as you remember, then resume your regular monthly schedule. A late dose creates a gap where heartworm larvae could develop further before being cleared, so try not to let doses run more than a few days late on a regular basis.

How should it be stored, and what’s the shelf life?
Store at room temperature, out of direct sunlight, tightly capped. Shake before each use. Discard if the solution changes color, smells off, or is past the expiration date on the bottle.

Note:

Doses reflect commonly referenced veterinary ranges and are for general informational purposes. Always confirm exact dosing and treatment length with a veterinarian.

Sources

• SIMPARICA TRIO (sarolaner, moxidectin, and pyrantel) — Official FDA Label, DailyMed
• Animal Drug Safety Communication: Neurologic Adverse Events Associated with Isoxazoline Flea and Tick Products — FDA
• Safety of moxidectin in avermectin-sensitive collies — PubMed
• Fact Sheet for Pet Owners and Veterinarians about Isoxazoline Flea and Tick Products — FDA