What is Selamectin (Revolution)? — A Complete Guide to the Parasites It Prevents All at Once

Skin & CoatQ&AMeongsiljang Veterinary Advisory Board

Selamectin (Revolution) is a topical medication that prevents six types of parasites, including fleas, heartworms, ear mites, and roundworms, all at once. We’ve summarized its safety, proper usage, and breeds to be cautious with.

What is Selamectin (Revolution)?

A dog having selamectin spot-on applied to the back of its neck

Selamectin is a topical (spot-on) parasiticide from the avermectin class that prevents and treats multiple parasites—including fleas, heartworm, ear mites, and roundworms—all at once. It’s easy to use: just apply it once a month to the back of your pet’s neck. What really matters is knowing which parasites it protects against and whether your pet meets the safe weight and age requirements. One of its biggest advantages is that it’s relatively safe for puppies over 6 weeks old, pregnant or nursing dogs, and even Collie breeds that are sensitive to ivermectin.

How Does Selamectin Kill Parasites?

Selamectin stimulates glutamate-gated chloride channels in the nervous and muscular systems of parasites. This causes excessive stabilization (hyperpolarization) of the nerves, leading to paralysis and death of the parasites. In mammals, the blood-brain barrier (BBB) normally prevents selamectin from penetrating the central nervous system, making it relatively safe for pets at recommended doses. However, in certain breeds with MDR1 gene mutations, this barrier function is weakened, which can increase the risk of neurotoxicity if overdosed. When applied to the back of the neck, it is absorbed through the skin into the systemic circulation and then redistributed along lipids secreted by sebaceous glands, allowing it to act against parasites throughout the body.

Parasites Prevented by Revolution

Selamectin is a "multi-parasite medication" that covers both external and internal parasites. The range of protection varies slightly between dogs and cats. We've summarized the key coverage areas in the table below, so please check if it matches the preventive needs for your pet.

Comparison of Covered Parasites: Dogs vs. Cats

Item	Dog	Cat
Fleas (adults and eggs)	True	True
Heartworm prevention	True	True
Ear mites	True	True
Sarcoptic mange mites	True	False
Roundworms	False	True
Hookworms	False	True
Ticks	True	False

There may be differences depending on the product label and regional approval. Check with your veterinarian before use.

How to Apply It Correctly

Selamectin must be applied directly to the skin. If it remains on the fur, absorption will be reduced.

Application site: Between the shoulder blades at the back of the neck, where the pet cannot reach to lick it.

How to apply: Part the fur to expose the skin, place the tip of the applicator against the skin, and squeeze the entire contents out in one go.

Post-application care: Avoid bathing or swimming for at least two hours, and do not rub or touch the area.

Frequency: Once a month, on the same date each time.

If you have multiple pets, keep them separated until the medication has dried to prevent them from licking each other.

Applying medication with a pipette to the skin between the shoulder blades

Veterinary Consultation Is Essential Before Use in These Situations

For puppies under 6 weeks of age, extra-small-breed dogs with very low body weight, pets with chronic skin conditions, or animals already receiving other dewormers or heartworm preventatives, please consult your veterinarian before using selamectin alone. In particular, if heartworm infection is already present, a veterinary examination and heartworm testing must be completed before starting any preventive medication. In cats, licking the isopropyl alcohol solvent may cause temporary drooling or foaming, which typically resolves on its own over time.

Can Collies and Shetland Sheepdogs Use It?

Certain herding breeds, such as Collies, Shetland Sheepdogs, and Australian Shepherds, may be sensitive to ivermectin due to a mutation in the drug susceptibility gene (MDR1). The good news is that veterinary pharmacology textbooks report that selamectin is significantly safer than ivermectin in these breeds. It can be used relatively safely in Collie-type dogs when administered within the recommended dosage range. However, exceeding the recommended dose is strictly prohibited. If you are concerned, the safest approach is to have your dog tested for the MDR1 gene mutation and use the medication under the guidance of your veterinarian.

A veterinarian examining the skin condition of a Collie.

How to Handle Side Effects

Side effects of selamectin are generally rare, but if they do occur, they may present as follows:

Hair loss or redness at the application site: This is temporary and usually resolves within 1–2 weeks.

Itching or scratching: This may be due to irritation from the alcohol solvent. Discontinue use if symptoms persist.

Drooling or foaming in cats: If the cat has licked the medication, provide water and monitor the situation.

Lethargy or decreased appetite: Although uncommon, seek veterinary care if these symptoms last more than 24 hours.

Vomiting, tremors, or gait abnormalities: These may indicate hypersensitivity to ivermectin; seek immediate veterinary attention.

Wiping off the applied medication is not very effective. Please inform your veterinarian based on the symptoms observed.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can I bathe my pet right after applying selamectin?

Please avoid bathing or swimming for at least 2 hours, and ideally for 24 hours. Since the medication is absorbed through the skin into the entire body, washing it off too soon can reduce its effectiveness.

Can ticks (hard ticks) be completely prevented?

Selamectin for dogs does have some effect on certain ticks, but according to veterinary pharmacology textbooks, macrocyclic lactones like selamectin do not kill arthropods such as ticks immediately, and it takes time for their effects to appear, making their tick-blocking efficacy limited. Therefore, it is difficult to consider them as providing complete protection against ticks. If your dog frequently visits areas with a high risk of tick exposure, consult your veterinarian about using an additional tick-specific preventive.

I missed a dose of heartworm prevention. Can I just restart right away?

If heartworm prevention has been interrupted for more than two months, a heartworm test should be performed first. Administering preventive medication when an infection is already present can cause shock, so consulting with a veterinarian is essential.

Is it safe for pregnant or nursing dogs?

Selamectin is known to be relatively safe for use in pregnant and nursing dogs, as well as in dogs and cats that are at least 6 weeks old. However, if it’s your first time using this medication, it’s safest to use it under a veterinarian’s prescription.

Can I use dog products on my cat, or cat products on my dog?

No, that’s not safe. The concentration and dosage of selamectin differ between dog and cat formulations. Always use the product specifically formulated for your pet’s species and weight to avoid toxicity or inadequate treatment.

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References

[1] Ahmed Z. Boothe. Handbook of Veterinary Pharmacology — Antinematodal Drugs (Selamectin section)

[2] Boy MG, Six RH, Thomas CA, et al. Efficacy and safety of selamectin against fleas and heartworms in dogs and cats presented as veterinary patients in North America. Vet Parasitol 2000;91(3-4):233-50.

[3] Maddison JE, Page SW, Church DB. Small Animal Clinical Pharmacology — Endectocides chapter