Capstar Pills for Flea Treatment – How Effective Is It?

Dogs and cats can be a joyful addition to the family, but when they’re outdoors they can pick up annoying pests, including fleas. While fleas are tiny insects, they can infest your precious pet and cause great annoyance. Worse, they can be brought into your home where they can get into your carpet and reproduce. Before you know it, you have a major problem with small fleas biting everyone in the family.

capstar for fleas

While fleas usually cause little more annoyance to humans with tiny red bites, they can also cause allergic reactions. These reactions can include large welts and swelling that can lead to bleeding and scars. The immune systems of young children are not as strong as adults, and they can greatly suffer from these bites.

Pets can also be greatly impacted by flea bites. They can cause skin infections and fur loss if they don’t have seasonal flea treatments.

Fleas can rapidly reproduce. One female flea can lay as many as 2000 eggs over a lifetime. It takes only three weeks for an egg to hatch. Adult fleas like to feed on your pet’s blood, then lay eggs, and drop off. The larval stage of fleas is minute and hard to detect. They can get into carpet, furniture, and even bedding.

There are many different types of flea treatments on the market today. Some are safer than others for pets. It’s important to do research, as your pets do need to be treated for fleas. Simply ignoring the problem is not an option, as fleas can transmit diseases to pets and humans.

One effective type of flea treatment is called Capstar. This is an oral tablet that you can give your dogs, puppies, cats, and kittens.

What Is Capstar?

Capstar is the brand name for a flea treatment for dogs, cats, and puppies and kittens. It’s generic or chemical name is nitenpyram. This is an ingredient that is in veterinarian-approved flea treatments for pets. It can be purchased online and is more affordable that bringing your pet to the vet’s clinic for treatment. Many pet owners have been successfully treating their pets with Capstar for years.

In laboratory and clinical studies, Capstar tablets have been proven safe for both dogs and cats to take, and kittens and puppies over 2 pounds in body weight and 4 weeks of age. Capstar can also safely be given to pregnant or nursing dogs and cats.

How Does Capstar Work?

Capstar is given to your dogs or cats through an oral pill that they swallow. It dissolves in their system and releases chemicals. The chemicals reside on the surface of their skin. When fleas hop onto the dog or cat and go to feed on them, the toxic chemicals transfer to the fleas, which kill them.

The nitenpyram is harmless to cats in minute amounts. Since fleas are so proportionately smaller than cats, only a minor amount of the chemical is required for it to be effective.

Captar is effective for killing fleas at their adult stage. It won’t kill them in the larval stage. It may take a few days of treatment before all fleas are killed on your pets. Once the fleas are killed, and you have thoroughly cleaned your home, given flea bath treatments for your pets, and hosed down your outdoor regions to kill any lingering fleas, then your family should be able to live in comfort for the rest of the season.

Flea eradication may be difficult, but it’s a necessary part of having a family. You’ll want to regularly treat your outdoor pets for fleas, but you won’t have to dose them as often with the pill once you stop seeing fleas around the home.

Some people choose to only treat their pets for fleas once they see them, while others treat them even if they don’t see fleas. While it’s most difficult to get rid of fleas once they enter your home, it’s also safer for pets, as you likely don’t want them to swallow insecticides too often. You can treat them for 6 days, up to 4 times a year, or only if you see the fleas. The choice is up to you.

What Makes Capstar an Effective Flea Treatment?

Capstar is effective as each tablet contains 11.4 to 57.0 mg of nitenpyram. This belongs to the same chemical class of neonicotinoids, a type of pesticide or insecticide. This chemical has been proven to kill fleas.

Fleas are also known to cause a skin condition on dogs called FAD–Feline Allergy Dermatitis, and miliary dermatitis in cats. This makes dogs and cats excessively itchy, and can eventually lead to skin infections that can negatively impact the health of your pet. Giving your pets Capstar can kill fleas that cause this condition.

Fleas can also transfer tapeworms to pets. Capstar can kill the fleas that carry these parasites so that they won’t transfer to your pets or your children.

Capstar can also be done in conjunction with other types of pet care products. These includes heartworm pills, corticosteroids, antibiotics, vaccines, de-worming pills, and other types of flea products, including flea shampoos.

What Are the Dosage Requirements for Cats & Dogs?

Capstar should only be given to pets that weigh more than two pounds in body weight. Puppies and kittens must be over four weeks old.

If you have both dogs and cats, since dogs are indoors/outdoors types of pets, then all dogs and cats in the home should be treated, as fleas can jump from dogs to indoor cats.

If you only have indoor cats, most likely you won’t need flea treatments. However, if there are fleas outside, it’s possible you can bring them in on your shoes and transfer them to your cats. When your brush and comb your cats, inspect them for fleas on a regular basis. They may need seasonal treatment if they show signs of fleas.

One pill or single dosage should be enough to kill the adult fleas on your dog or cat. It’s important after a dosage to also treat your home–indoors and out–for fleas, so that your pets won’t pick up any more fleas from outside.

If your pet gets re-infested with fleas, then you can do a second treatment. If the flea infestation is really bad, then give another dosage as often as once per day, but only up to 6 total days. There may be lingering fleas in the home that can re-infest your pet.

For small dogs or cats from 2 to 25 pounds, one tablet of 11.4 mg can be given. For larger dogs of 25.1 to 125 pounds, one tablet of 57.0 mg may be given. If your dog is larger than 125 pounds, consult with a veterinarian first.

How Long Does One Treatment of Capstar Last?

One single box of Capstar contains 6 tablets. Each tablet is effective for 24 hours. You can give one pill for each of 6 days. It’s recommended to give your pets a break in treatment if you still see fleas on them, or to try other types of effective flea treatments.

Capstar will start working within 30 minutes of being given to your pet. In lab studies, it has been proven to provide 90% effectiveness at killing fleas on dogs within four hours, and on cats within six hours.

Capstar should kill all fleas on your pets within one day. If not, you can safely give them one tablet per day until the box is empty.

Shortly after treatment you may being to notice your dog or cat scratching themselves. This is a normal process, as the fleas begin to die. This is a reaction to the fleas themselves, and not to the drug.

24 hours should be adequate time for you to deal with the fleas in the inside and outside of your home. With some effort, you should have a flea-free home in about one week.

How Do I Give Capstar to My Dog or Cat?

You may place it in your dog’s mouth so they can swallow it. Cats will try to spit it out. You may need to open their jaws up wide and drop it down their throat. If you have difficulties, you can use a pill popper.

capstar dangers

You may also wish to hide it in their food. You can also buy treats where a pill can be concealed.

Capstar Precautions

Please follow these precautions and warnings so that you can safely give your dogs and cats their flea treatment.

    • Capstar is only for pets, it’s never for human consumption.
    • Keep Capstar stored out of the reach of pets or children.
    • Only give it to pets over the age of 4 weeks, and who are more than 2 pounds in body weight.
    • With any type of oral medication, there can be side-effects and abnormal reactions. You may wish to dose your pets early in the weekday morning, so if you need to take them to the vet for an adverse reaction, you can find a clinic open at that time.
    • Treat all pets in your home, even if you’ve only seen fleas on one.
    • Be sure to follow the body weight and milligram dosage requirements.
    • There have been some reactions noted in cats that may include hyperactivitiy, panting, meowing, and excessive grooming. These are all normal.
    • If after treatment your pet starts foaming at the mouth, or becomes lethargic, take them to the vet clinic immediately.
    • Store the product at regular room temperature from 15-25°C.
    • Consult with a veterinarian if you have any questions or concerns about using Capstar on your pets.

Treating Your Home for Fleas

Many people erroneously think that giving a pill to their pets is going to magically eradicate the fleas in one day. This type of flea treatment is a bit different than Advantage, which also sterilizes the fleas. Capstar simply kills adult fleas. It’s a much safer way to treat pets, as often other insecticides that kill fleas at all stages can be more harmful to pets. The key is to kill the adult fleas, and deal with the rest of the home yourself.

It’s important to wash everything in the home, and vacuum all rugs and furniture on a regular basis. The outdoors should be regularly hosed down with water, which is the most effective way of killing fleas. Since fleas involve a 4-life stage process, you’ll have to keep up with regular cleaning of indoors or outdoors for at least 4 weeks.

Your pets may also benefit from a topical treatment of coconut oil to the backs of their necks. This has been shown as being an effective anti-flea preventative too.

When you first discover your pet has fleas, it can be stressful. Then you give them their first treatment of Capstar and start to treat your home. Soon it gets better. The following days really are only in clearing out any stragglers.

Final Thoughts on Capstar for Fleas

Using Capstar on pets is an effective way to treat dogs or cats for fleas. While many people don’t like the idea of using an insecticide on their pets, the medical conditions that can result from flea infestations can be serious, and even be transferred to humans.

As long as you follow the dosage and weight requirements, this medication can be used for both dogs and cats, so you never have to worry that you’re mixing up their flea medication treatments. If you can easily give your dog or cat pills, pill treats, or hide it in food, then Capstar may be the best flea treatment to give your pets, that’s both affordable and effective.

Capstar is the same medication sold by your vet, but since there’s such a high markup from a vet clinic, you can simply purchase it online and save money.

Soon your home will be free of annoying fleas and you and your family can rest easier knowing that there won’t be annoying or itchy flea bites when playing with your pets.


  1. Patti Drier June 22, 2018
  2. Lizzy January 17, 2020

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