Selamectin Topical for Dogs and Cats

Medically Reviewed by Joshua Conrad, PharmD on October 10, 2024
Written by Kathleen Claussen, DVM
6 min read

Selamectin (Revolt, Revolution, Selarid, Senergy) is an antiparasitic medicine for use in dogs, puppies, cats, and kittens.  It is a liquid that is given topically (applied to the skin) at the back of the neck once a month. Selamectin is classified as an avermectin antiparasitic that is effective against fleas, ticks, heartworms, and ear mites in dogs and cats.  It is FDA-approved for dogs and puppies at least 6 weeks old and cats and kittens at least 8 weeks old.

Selamectin can be used for treatment and control of sarcoptic mange in dogs, control of the American dog tick in dogs, and treatment and control of hookworms and roundworms in cats.  It can also be used “extra-label” or “off-label” in small animals for the treatment of notoedric mange, nasal mites, and other conditions.  “Extra-label” or “off-label” means that there is evidence of safe and effective use but the FDA has not approved that use. When used for extra-label treatments, selamectin may be given more frequently than once a month.

Selamectin is generally well-tolerated in animals. It starts to be effective within 4 to 8 hours and reaches full effectiveness within 7 days.  

Selamectin is available by prescription from your veterinarian or from a veterinary pharmacy.  It is available as a topical liquid in various doses.

Selamectin is a topical liquid placed at the back of the neck to kill fleas, to prevent heartworm disease, and to treat ear mites.  Dogs should be at least 6 weeks old and cats should be at least 8 weeks old before getting selamectin.

Give selamectin every 30 days (monthly) without stopping for best results. For some uses, your veterinarian may prescribe a different dosing schedule.

To apply selamectin, make sure the skin at the back of the pet’s neck is dry. Using the appropriate tube, part the hair and squeeze the contents of the tube directly onto the skin.  Do not touch that area until it is completely dry.  The selamectin will be absorbed into the bloodstream. Avoid bathing your dog within 2 hours of application and your cat within 24 hours of application. Do not allow your pet or other pets in the household to rub or lick the application site until it dries.

Always follow your veterinarian’s directions for giving medicines to animals. Remember to tell your veterinarian about any medicines, vitamins, supplements, or herbal therapies that you are giving your pet. Talk to your veterinarian before stopping any pet medicines.  

  • Selamectin is well-tolerated by animals, including puppies and kittens.
  • Selamectin is FDA-approved for use in dogs, puppies, cats, and kittens.
  • Selamectin starts to work within the first 4 to 8 hours after application.
  • Selamectin is a topical product applied every 30 days.
  • Selamectin is effective against fleas, heartworm, and ear mites.

You and your veterinarian should monitor your pet for improvement of their condition as well as for side effects of the medicine. You should monitor for signs of improvement such as fewer live adult fleas and ticks, less itching, and less scratching. If selamectin is used for ear mites, follow-up ear tests may be done by your veterinarian. If selamectin is used for intestinal parasites, follow-up fecal (stool) tests may be checked. If selamectin is used for skin mites, skin tests may be rechecked by your veterinarian.

Before giving selamectin, dogs need to have a negative heartworm test. The heartworm test should then be repeated yearly. If there are missed doses of selamectin, a heartworm test should be repeated before restarting selamectin and again in 6 months.

Do not use selamectin in animals that are allergic to it. Do not use selamectin in dogs that are less than 6 weeks old.  Do not use selamectin in cats that are less than 8 weeks old. Use with caution in animals that are in poor body condition (underweight), sick, or frail. Although it appears to be safe to use in pregnant and nursing pets, give it with caution in these animals. Use with caution in dogs or cats with the MDR1 gene mutation. Do not use selamectin near a flame as it is flammable.

Selamectin is usually well-tolerated in animals. Side effects in dogs and cats are rare but may include:

  • Scratching at the neck
  • Slight hair loss at the application site
  • Powdery residue after application has dried
  • Diarrhea or loose stools
  • Vomiting
  • Mild skin reactions, redness, or hives
  • Decreased appetite
  • Tiredness
  • Difficulty breathing
  • Difficulty walking
  • Muscle tremors or seizures

Most side effects occur if the selamectin is accidentally given by mouth instead of being applied to the skin. You might see side effects such as excessive drooling, increased urination (peeing), vomiting, decreased appetite, or tiredness.

If you suspect that your pet is having a serious side effect or may have been overdosed, call your veterinary clinic immediately. If it is outside of regular office hours, you may contact a local emergency veterinary hospital or an animal poison control center. 

You can reach the ASPCA Animal Poison Control Center at 888-426-4435 or the Pet Poison Helpline at 855-764-7661.

Using multiple medicines can sometimes change how your pet’s medicines work or increase your pet’s risk for serious side effects. Always tell your veterinarian about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements that your pet is using.

During clinical studies, selamectin was used safely with vaccines, deworming products, other antiparasitic medicines, antibiotics, corticosteroids, collars, shampoos, and dips (used for external parasite treatment).

Some medicines that may interact with selamectin are spironolactone, “azole” antifungals such as itraconazole or ketoconazole, cyclosporine, diltiazem, and erythromycin.  

This may not be a complete list of medicines that can interact with acepromazine. Always check with your veterinarian.

  • Keep selamectin out of the reach of children.
  • Wash your hands after giving selamectin to your pet.
  • Do not handle selamectin if you are allergic to it.
  • Avoid contact of selamectin with eyes, skin, and clothing.
  • Avoid contact with the area of application on your pet until it is dry.

Selamectin is well-tolerated by animals and the risk of an overdose is low. If you are concerned your pet is having an adverse reaction or if you suspect your pet has ingested selamectin or has been given too much, call your veterinarian or veterinary emergency clinic immediately.

If your pet misses a dose, give the dose when you remember and then continue with the rest of the medicine at the correct dosing time. Do not double the dose of the medicine. If more than 8 weeks have passed since the last dose, start the monthly selamectin again. Your dog will need to have a heartworm test performed in 6 months to determine if there is heartworm disease. It takes 6 months from the bite of an infected mosquito till a dog may test positive for heartworm disease.

Store selamectin in the original packaging below 86 F (30 C).  Protect from flame, fire, or igniter.