Selamectin for Scorpion: Uses, Dosing & Side Effects

This information is for educational purposes only. Never give your pet any medication without your veterinarian's guidance. Dosing, frequency, and safety depend on your pet's specific health profile.

Selamectin is a topical prescription antiparasitic in the macrocyclic lactone family. It is applied to the skin, usually at the base of the neck, and is widely used in dogs and cats rather than scorpions. If your scorpion page is part of a broader medication library, it is important to know that selamectin is not a routine medication for pet scorpions and should only be discussed with an exotics veterinarian if they specifically recommend it.

In dogs and cats, selamectin is sold under brand names such as Revolution, Revolt, SelaSpot, Paradyne, and Stronghold. It is labeled for monthly parasite control and prevention, with a recommended minimum dose of 2.7 mg per pound (6 mg/kg). The medication is prescription-only because your vet may need to confirm the parasite involved, check heartworm status, and choose the right product size for your pet.

Selamectin is designed for topical use only. The tube contents are placed directly on dry, unbroken skin and should not be massaged in. Temporary hair clumping or a powdery residue can happen at the application site. Because the liquid contains alcohol, it should not be applied to irritated or broken skin.

In dogs, selamectin is commonly used for flea prevention and control, heartworm prevention, ear mites, and sarcoptic mange. Some labels and regional products also include certain tick claims, but those vary by product and country, so your vet should confirm exactly what a specific brand covers.

In cats, selamectin is used for fleas, heartworm prevention, ear mites, and treatment of some intestinal parasites, especially roundworms (Toxocara cati) and hookworms (Ancylostoma tubaeforme). It is one of the better-known monthly topical options because it covers both external and internal parasites in a single prescription product.

Your vet may also use selamectin off label in some situations. Off-label use is common in veterinary medicine, but it should still be guided by your vet because the dose interval, number of treatments, and safety considerations may differ from the package directions.

Selamectin dosing is based on body weight and the specific product tube size. The labeled minimum dose is 2.7 mg/lb (6 mg/kg) applied topically once monthly. Common package sizes include 15 mg, 30 mg, 45 mg, 60 mg, 120 mg, 240 mg, and 360 mg tubes, with different strengths for dogs and cats. For very large dogs, your vet may direct you to use a combination of tubes to reach the correct dose.

Most pets receive selamectin every 30 days for ongoing parasite prevention. For flea and heartworm prevention, monthly use is standard. For ear mites or sarcoptic mange, your vet may recommend one dose or a series of doses depending on the parasite, severity, and response to treatment. If a monthly dose is missed, give it when remembered and restart the monthly schedule from that date unless your vet advises otherwise.

Apply the full tube to dry skin at the base of the neck, where your pet cannot easily lick it. Do not split tubes between pets unless your vet specifically instructs you to do so. Dogs should generally not be bathed within 2 hours of application, and cats should avoid bathing for at least 24 hours when heartworm prevention is the goal. Puppies under 6 weeks and kittens under 8 weeks should not receive labeled selamectin products unless your vet gives different instructions.

Most pets tolerate selamectin well, but side effects can still happen. The most common issue is a mild reaction at the application site, such as temporary hair loss, hair clumping, discoloration, or slight skin irritation. In cats, transient localized hair loss near the application site has been reported in about 1% of treated pets in pre-approval studies.

Less common side effects include vomiting, diarrhea, decreased appetite, lethargy, drooling, faster breathing, itchiness, redness, and muscle tremors. Rare neurologic effects such as incoordination or seizures have been reported in dogs. If your pet seems weak, unusually sleepy, wobbly, or distressed after application, contact your vet promptly.

Use extra caution in pets that are sick, underweight, debilitated, pregnant, lactating, or not yet evaluated for heartworm infection. Some dogs with the MDR1/ABCB1 gene mutation, including certain Collie- and Shepherd-type breeds, may be more sensitive to macrocyclic lactone medications. See your vet immediately if your pet has trouble breathing, collapses, has a seizure, or develops severe swelling or hives after treatment.

Selamectin is often used safely alongside many common veterinary medications, but that does not mean interactions are impossible. Your vet should know about all prescriptions, preventives, supplements, and herbal products your pet receives before starting treatment.

Extra caution is advised in dogs with the MDR1/ABCB1 mutation, especially if selamectin is combined with other drugs that can affect drug transport in the body. VCA lists medications such as cyclosporine, diltiazem, erythromycin, itraconazole, ketoconazole, spironolactone, and verapamil as drugs to discuss carefully with your vet in these patients.

It is also important not to layer multiple parasite products without guidance. Combining flea, tick, mite, or deworming medications may be appropriate in some cases, but the plan should be intentional. If your pet is already on another heartworm preventive, flea product, or mite treatment, ask your vet whether selamectin should replace it or be coordinated with it.