Selamectin for Dogs and Cats

With so many different flea, tick, and heartworm preventatives available for dogs and cats it’s sometimes difficult to keep track. Selamectin is a topical antiparasitic medication for dogs and cats prescribed for various parasite infections. Selamectin is the active ingredient found in multiple products including Revolution For Dogs, Revolution for Cats, Selarid for Dogs, Selarid for Cats, Revolt for Cats, Revolt for Dogs, Senergy for Cats, and Senergy for Dogs. Selamectin is used in dogs and cats to prevent heartworm disease and treat and control flea and ear mite infestations. In dogs, Selamectin also controls tick infestations of the American dog tick and treats sarcoptic mange. In cats, it also treats intestinal roundworm and hookworm infections. 

How Does Selamectin Work?

Medications containing selamectin for dogs and cats are applied to the skin and are absorbed with the natural oils secreted by their skin. Selamectin works to kill parasites by interfering with the nervous system of the infecting parasite. 

What Parasites Does Selamectin Work Against?


  • Prevents heartworm disease
  • Treats ear mites
  • Treats sarcoptic mange
  • Controls American Dog tick infestations
  • Kills adult fleas and prevents flea eggs from hatching


  • Prevents heartworm disease
  • Treats ear mites
  • Treats hookworms & roundworms
  • Kills adult fleas and prevents flea eggs from hatching

Selamectin Prevents Heartworm Disease

Selamectin is labeled for the prevention of heartworm disease in dogs and cats. It is important to know that Selemctin only prevents heartworm disease and does not treat existing heartworm infections. This is because it is only effective against killing the immature heartworm larvae (Dirofilaria immitis) and does not kill the adult stage heartworms found in animals with existing infections. 

Products with Selamectin

Does Selamectin Require a Prescription?

Products containing Selamectin for dogs and cats require a prescription from a veterinarian because of their ability to prevent heartworm disease. The American Heartworm Society and most veterinarians recommend an annual heartworm test before prescribing a heartworm preventative for your dog or cat. This is because dogs and cats with existing heartworm infections can have serious complications after taking preventatives.

It is always recommended to speak with your veterinarian about the right parasite preventative product for your dog or cat’s needs. Your veterinarian can recommend the best product for your dog or cat based on your location and the type of parasites they may encounter. 

This information is not intended to diagnose or treat any disease and is purely educational. Please seek advice from your pet’s veterinarian with any questions regarding the health of your pet. 

Sentinel Heartworm Availability

Sentinel is Back In Stock at VetRxDirect!

Sentinel, the popular oral heartworm and flea preventative, is once again available at your pet’s online pharmacy, VetRxDirect.

Sentinel GroupSentinel (milbemycin oxime / lufenuron) is a palatable one-a-month prescription heartworm and flea preventative pill for dogs and puppies. Sentinel also controls some intestinal parasites. See the product’s package insert and ask your veterinarian for more information.

Sentinel’s arrival on our shelves is just in time for spring. Now is the time when many dog owners make appointment with their pet’s veterinarian for spring exams, including a heartworm test. This is also a good time to ask your veterinarian if your dog should switch to sentinel or stay on his/her current heartworm preventative. Your veterinarian who has examined your pet is the best source for this information.

Be sure to sign up for our newsletter and check our blog regularly to receive updates on the availability of hard to find pet drugs and pet supplies.

How to Get Rid of Fleas in Your House

Household Treatment for Fleas

Most dog and cat lovers accept fleas as an inevitable part of pet ownership.  But that is often because they deal with infestations the wrong way.  Because they generally only treat the affected animal, they miss the other 95 percent of fleas that are living in their homes and yards. How could this be? Don’t parasites have to feed on the pet? Yes, but only if they’re fully grown.

Only about five percent of fleas are adults, and those are the ones that bite! The rest are in the egg, larvae, or pupae stage of the flea life cycle. The future pests that will one day reach adulthood (unless you deal with them first) are more likely to be growing in your home or yard than on your dog or cat.  And this is why when you only treat your furry friend, your pet will soon start scratching again when the next generation of fleas are old enough to feed.

In order to eradicate an infestation, you must kill all of the fleas in your home, yard, and on your pets. And you must do so on the same day!  It may take you a few hours, but total flea control can save your pets from months of needless suffering.  Not to mention the fact that fleas also bite humans! So set aside a free day and assemble your arsenal.

Step 1 in the Fight against Fleas in your Home – Vacuum your entire home!

Fleas tend to hide and grow in dark corners and crevices, under furniture and beds, on carpets and rugs.  A thorough vacuuming not only sucks up fleas when they are away from their hosts, the vibration may also force immature parasites to come out of their cocoons, which makes them more vulnerable to flea bombs, sprays, and other insecticides.

You won’t be able to see them, but most of the fleas you vacuum up will be in the egg, larvae, or pupae stage and will be growing on your carpet or floor. After the vacuuming is done, empty the contents into a plastic bag and secure it. You don’t want any of the fleas you evicted to escape.

Step 2 in the Fight against Fleas in your Home – Spray insecticides!

Sold in fogger, flea bomb, and aerosol form, these products are designed to eliminate fleas in all stages of the life cycle.  They should be applied to all rugs, floors, carpets, and soft upholstered furniture. Also remember to spray under all cushions, beds, and in dark areas.

Knockout Room and Aera Fogger from Virbac

Knockout Room and Aera Fogger Available at VetRxDirect

The most effective flea control products on the market often contain insect growth regulator, which is a chemical that sterilizes fleas and their eggs for several months.  The Room and Area Fogger from Virbac not only contains that chemical, it also has others to kill adult fleas immediately and residually.  In other words, even those that manage to survive the initial application will die off in time.  The standard 6 ounce bottle can treat up to 6000 cubic feet of space.

While it is true some sprays designed for indoor use can also be used to kill fleas in your backyard, concentrated sprays are generally much more effective for outdoor use.  Yard Spray Concentrate, also from Virbac, is a water based solution that will not harm grass or plants. It comes complete with an easy to use hose end applicator and can cover up to 6,000 square feet of lawn.

Step 3 in the Fight against Fleas in your Home – Treat your pets

From tablets to chewables to sprays and shampoos, there are many different and effective ways to treat your dog or cat for flea infestation. Since we cannot discuss all of them here, we will talk about the old standby—shampoo. Flea and tick shampoos are arguably the easiest and most affordable way to kill a bunch of pesky parasites in a matter of minutes. Although it is not a permanent solution, since the chemicals that eradicate the infestation will only stay on your furry friend’s skin for a couple of days, it will stop the scratching while you deal with the fleas in your home and yard.

Adams Plus Flea and Tick Shampoo

Adams Plus Flea and Tick Shampoo Ships Fast From VetRxDirect.

Mild enough to be used as a regular cleanser, Adams Plus Flea & Tick Shampoo with Precor is one of the top selling products on the market. In addition to eliminating infestations, the shampoo will also help deodorize and condition your pet’s coat! The solution contains soothing aloe, lanolin, oatmeal, and, of course, insect growth regulator. Adams Plus kills fleas, flea eggs, lice, and ticks in one shot.

After you have successfully eradicated your house of all the stages of fleas, talk to your veterinarian about the best topical or oral flea preventative for your area. The most trusted names are available at VetRxDirect, your pet’s online pharmacy.

Which products and practices have worked for you? Please leave us ideas in the comments section below so we all can learn how to eradicate our homes of this these little nuisances.

All of us here at VetRxDirect are here to help get you the best products available quickly, when you need them.


Prevent the Flea Life Cycle on Your Pet

Fleas are the most common external parasite on dogs and cats. They tend to build up during the summer months and early fall, but can be a year round problem indoors.  Fleas cause itching and irritation which leads to dermatitis that can become severe if your pet becomes allergic to the flea bites.

Fleas prefer dogs and cats, but when they are in sufficient numbers they will start to bite you. Control of fleas has always been a challenge because only adult fleas live on the pet. The majority of the flea population (eggs, larvae, and pupa) live off the pet, in and around the house. The adult fleas cause all of the symptoms, but represent less than 10% of the total flea life cycle population.

The Flea Life Cycle

Eggs are laid in the hair coat of pets and fall off in and around the house. Eggs are resistant to many insecticides. Eggs hatch and develop into larvae which feed on digested blood excreted by the adult flea. Larvae then develop into pupae (cocoons) and can remain dormant or develop rapidly into adults. Pupae are also resistant to insecticides. The life cycle of the flea is about 21 days in the right conditions but can be as short as 16 days. Adult females live 4-6 weeks and can lay up to 40 eggs per day. Once adult fleas emerge they are very hungry and will immediately seek a blood meal from your pet. Yuck!

Flea Control

Physical cleaning and vacuuming your environment is very helpful in reducing the amount of eggs and immature fleas. But eggs and immature fleas are very small and can hide in the smallest places and some stages can lay dormant until the right conditions exist. Total flea control requires cleaning and treatment of the environment as well as treatment of the pet. It is much easier to prevent fleas than treat them once they have infested the house and pets.

Common Flea Control Products:


Lufeneron is available in a once per month tablet or oral solution branded Program and in the prescription heartworm medicine branded Sentinel. Lufeneron keeps flea eggs from hatching, helping to break the flea life cycle. It is also available from your veterinarian as a six month injection for cats.

Pyriproxifen (Nylar)

Pyriproxifen (Nylar) is an insect growth regulator found in many household sprays and foggers. Brands include Mycodex and Virbac Knockout. One treatment can last up to 150 days, but always follow the instructions found on the product’s label.


Imidacloprid is a topical adult pesticide for pets applied monthly. Advantage II for Cats and Advantage II for Dogs contain imidacloprid. It is combined with permethrin for tick control in dogs in the branded product Advantix II. Advantix should not be applied to cats. Imidacloprid is combined with moxidectin in the prescription topical medications for heartworm prevention, the branded products Advantage Multi for Cats and Advantage Multi for Dogs.


Fipronil is a topical adult insecticide found in Frontline, Certifect, Effipro for Cats, Effitix for Dogs, and many other products. These products are applied topically once a month. Fipronil controls both fleas and ticks. In Frontline Plus and Certifect, it is combined with S-Methoprene, an insect growth regulator, to control adult and immature fleas. Certifect and Effitix should not be used on cats.


Selamectin is a prescription medicine for dogs and cats that controls fleas and heartworms as well as other listed parasites. Selamectin is available as a product branded Revolution for Cats and Revolution for Dogs and is applied topically to the pet once per month


Nitenpyram is the flea medicine contained in Capstar Tablets. It kills fleas rapidly as soon as it is ingested by the dog or cat. It only lasts a short time but can be repeated daily as needed.

Secondary Problems Caused by Fleas

Fleas are not only a nuisance, they can also cause severe diseases in pets. Fleas carry tapeworm larvae which can lead to tapeworm infections in dogs and cats. All pets infested with fleas should be wormed for tapeworms after the fleas are under control. Virbantel is an excellent tapeworm treatment.

Even a few fleas can cause skin problems in dogs and cats and may not even be readily observable. This may cause skin problems which are hard to discern from seasonal allergies since both are common in the spring, summer, and fall.

It is easier and less expensive to prevent fleas than treat them once they have infested your house and pets. So, start your pet on a flea preventative today.

Which flea preventatives have you used on your pet? How did the flea medicine work? Do you have suggestion on controlling fleas in the home? Please leave your comments below.

VetRxDirect is here to help keep your pet flea free,