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Siberian Husky Scratching Flea Pills

The flea circus your grandfather told you about was cute. Fleas on your dog are not. If your home feels like it is turning into your very own flea Cirque du Soleil, you definitely need to take some action.

You’ve probably heard someone in your life mention flea pills for dogs. These pills can be a very effective method for getting rid of fleas on dogs, and there are more options available today than ever before. Here is what you need to know about flea pills to help you choose the best option for your dog.

What Are Flea Pills?

Flea pills are oral insecticides that help control, treat, and prevent flea infestations in dogs. There are several different types of flea pills out there commonly prescribed by veterinarians. Each has a different active chemical ingredient that targets fleas in a unique way.

Some flea pills kill adult fleas, others kill larvae, and some inhibit a flea’s ability to lay eggs. Knowing which part of the flea life cycle the pill targets is essential for effective flea control, so make sure you read the label carefully and talk with your veterinarian.

The type of flea pill that is best for your dog depends on your situation. If you are looking for an oral monthly preventative, then a fast-acting flea pill that only stays in your dog’s system for a few days is probably not your best bet. On the other hand, if your dog is suffering from flea allergy dermatitis, then a fast-acting flea adulticide is exactly what you need.

Do I Need a Veterinarian to Get Flea Pills?

Flea control measures have changed a lot over the years. The flea dust that your local hardware store used to sell might not be the best choice when compared to some of today’s more advanced options. As a client, navigating around the promotional material of pharmaceutical companies and the thousands of contradictory websites discussing flea pills is tricky.

Luckily, you don’t have to come to the decision on your own. Your veterinarian knows a lot more about the different options and can guide you toward the one that will be most effective for your dog. More importantly, your veterinarian is aware of any potential side effects and medication interactions between flea pills and other preventatives and prescriptions. Your veterinarian can let you know if there are any breed predispositions to adverse effects, and if there is anything else in your dog’s medical history that could be relevant.


Fleas are a nationwide problem. In some areas, fleas have developed resistance to certain insecticides. Your veterinarian is your best source for discovering which flea pill will be most effective against a resistant flea population.

It is possible to order some flea pills for dogs online or from a pet store without a veterinarian, but many of these pills do require a prescription. Choosing to medicate your dog on your own without the oversight of a veterinarian is always risky, and in some cases can lead to flea resistance and ineffective treatments that will ultimately cost you more in money, time, and your dog’s comfort.

Flea Pills for Dogs vs. Topical Applications and Collars

Flea pills are just one option for flea treatment and prevention. Topical applications, flea collars, shampoos, and environmental insecticides are also options to help you deal with a flea infestation.

The decision to use an oral flea preventative/insecticide is up to you and your veterinarian. Flea resistance to certain products can play a role in this decision-making process, as can concerns regarding safety or personal preference about topical applicants and flea collars. Pre-existing medical conditions, your dog’s age, and whether or not she is pregnant can also help determine the right flea product for your dog.

In some cases, a fast-acting flea pill that kills fleas within a few hours can be part of a treatment plan for flea allergy dermatitis. Your veterinarian might recommend a fast-acting flea pill preventative to help relieve your dog’s symptoms or recommend an over-the-counter flea pill, like Capstar, in addition to a monthly preventative.

Types of Flea Pills for Dogs

The Merck Veterinary Manual lists the following chemical compounds in flea pills that are most effective against fleas:

  • Afoxolaner
  • Fluralaner
  • Nitenpyram
  • Spinosad


Most of us have only heard of these compounds by their brand names, but it is useful to know the active ingredients as you do your research.

The following flea pills for dogs can help you eliminate unwanted parasites from your pup.

NexGard (Afoxolaner)

NexGard (afoxolaner) is a flea adulticide, which means it kills adult fleas. Once a flea attaches to your dog and begins to feed, the active ingredient, afoxolaner, acts to kill the adult fleas. This interrupts the life cycle by killing the adults before they can lay eggs.

NexGard lasts for up to 30 days and also kills ticks, making it an ideal monthly oral preventative for dogs. While NexGard is generally well tolerated, some of the side effects of NexGard for dogs include vomiting, diarrhea, dry/flaky skin, lethargy and lack of appetite.

Bravecto (Fluralaner)

Bravecto (fluralaner) is a relatively new flea pill. It kills attached and feeding fleas and ticks and takes effect quickly, killing both adult and juvenile fleas within 8 hours and ticks within 12 hours. The preventative lasts for 12 weeks, which means you only have to give it every three months.

Possible side effects of Bravecto for dogs include diarrhea, vomiting, loss of appetite, drooling, gas, lethargy, and excessive thirst.

Capstar (Nitenpyram)

Capstar (nitenpyram) is a fast-acting, over-the-counter flea pill for dogs. Nitenpyram is absorbed into the bloodstream very quickly, and the drug starts to work within 30 minutes of ingestion, killing more than 90 percent of fleas on your dog within 4 hours. Capstar only kills adult fleas that have fed on your dog, and the drug leaves your dog’s system after 24-to-48 hours. This makes it effective for immediate relief, but not as a long-term treatment option or preventative.

Side effects of Capstar for dogs are mild, but can include stomach upset and itchiness. The itchiness is a result of the dying fleas and should resolve within a few hours. Watch out for allergic reactions to nitenpyram.


Comfortis (Spinosad)

Comfortis (spinosad) is a monthly preventative flea pill that comes in a chewable tablet. The active ingredient, spinosad, causes paralysis and death in adult fleas, killing them before they can lay eggs. This interrupts the flea’s life cycle if given as a monthly preventative, helping to treat and prevent infestations. Comfortis begins killing adult fleas within 30 minutes after ingestion, and has a demonstrated 100 percent effectiveness within 4 hours.

The most common side effect associated with Comfortis is vomiting. Less common side effects include lethargy, diarrhea, itchiness, drooling, shaking, ataxia, and seizures. Comfortis does not protect against ticks.

Future Flea Prevention

Thank goodness, fleas are preventable. Once you have decided on a flea pill for your dog, be sure to follow up with any additional steps recommended by your veterinarian. In most cases of flea infestations, you will also have to treat your home and yard for fleas, along with any other pets in the household, and you will need to stay on top of your flea and tick preventative schedule in order for it to remain effective.