Fleas aren't only about itching. Biting fleas can cause disorders in dogs: flea allergy dermatitis, secondary skin infections, tapeworms, and even anemia. Once your dog becomes infested with these parasites, it's can difficult to get rid of them all. Good flea pills for dogs will not only kill parasites, but also prevent re-infestation later on.

Because dog flea pills contain strong chemical ingredients, it's imperative to talk with your veterinarian before giving your pet any kind of medication, including flea preventatives. Oral flea and tick preventatives for dogs are gaining popularity with vets and pet owners, but they aren't safe (PDF) for every dog.

Similar to topical flea treatments for dogs, flea pills usually only need to be administered once per month. But unlike topical treatments, dog flea pills are more convenient for dog owners. Below we'll talk about the effectiveness and safety of dog flea pills, how they work and how to use them, review the best flea pills for dogs we liked in the past.

Types, Safety and Efficacy of Dog Flea Pills

Oral flea medications for dogs is the most convenient way to prevent parasites on your pet, but because they are administered orally, many pet owners have concerns over their safety. Fortunately, there's been a lot of research in testing how a flea pill for dogs works, and the safest way to administer these parasite preventatives.

In the US and Europe, there are several popular and well-studied brands and types of prescription and over the counter dog flea pill types that pet owners have to choose from. Most of these will be prescribed by a veterinarian.

Some other flea pill for dogs products are available over the counter and are designed to do the same job – kill fleas, ticks and other common dog parasites. However, there will be a lot less research available for the OTC dog flea pill products.

So what's the difference between vet prescribed and over-the-counter flea pills?

The difference are active ingredients. Over-the-counter products may use more of natural ingredients, and be less harmful and less toxic. At the same time, they may also be less effective than scientifically proven strong chemicals like those above.

Out of the five above mentioned, the one that stands out is Capstar (nitenpyram). This brand is usually cheaper and works as a short-term quick solution to rid dogs of fleas. It was shown to effectively kills fleas for at least up to 24 hours. The other ones are all long-term solutions, administered to a dog orally once a month.

You will also notice that every brand of vet prescribed flea pills has a different active ingredient. All of them are generic names for insect growth inhibitors and regulators, and insecticides to control the flea population. Ultimately, they all do the same job. What you have to be careful about is whether a specific insecticide is fine to be used with your dog.

Which Flea Pills for Dogs Are Most Effective?

There's been a number of studies testing the efficacy of these dog flea pill products and comparing them among each other. The more popular brands have more research behind them but it's also important to note that many of these studies were funded by the companies themselves.

In a well-known 2014 study, Bravecto (fluralaner) was compared to topical treatment Frontline (fipronil) and the researchers concluded much higher efficacy of Bravecto over Frontline (Rohdich et al. 2014). Both dog flea pills were shown to be safe for canines.

In a 2014 study with cats, Comfortis (spinosad) was shown to be an effective treatment against fleas and safe for pets to use (Franc et al. 2014). Then, a blinded, randomized, controlled study with dogs compared spinosad active ingredient with the effectiveness of Bravecto (fluralaner) and found the latter to be 3 times more effective than spinosad flea treatment (Meadows et al. 2014).

A much older, independent study with dogs and cats tested the effectiveness of a few general dog flea pill products' active ingredients, and found that oral flea medication reduces the number of fleas by 97.3% within the first 7 days. Overall, all products showed the results of 89.5% flea reduction by day 28 and 100% flea reducation by days 80-90, on average (Dryden et al. 2001).

There is a lot more research available on the efficacy and safety of these top rated flea pills for dogs, and the consensus is that they're generally safe and extremely effective. However, side effects – while rare – may occur. Most common adverse effects are lack of appetite, vomiting, diarrhea, lethargy, itching, difficulty breathing, or reddened skin.

The same cannot be said about ticks, however.

Majority of these studies prioritized fleas. Some have also found the products to be effective against ticks, too; however, the evidence isn't as strong. Furthermore, another study from 2016 with dogs tested several products (Pfister et al. 2016). They worked well for fleas, but tick re-infestation occurred just 7 days after the treatment.

dog tick infestation after treatment
Tick infestation 7 days after treatment. Credit: Dr M. Canfield / Pfister, 2016

Tick infestation is much harder to deal with when the case is severe. Consultation with a vet and a proper plan for treatment using prescription pills will be required in some cases.

How Do Recommended Flea Pills for Dogs Work?

Keep in mind that anti-flea pills for dogs work as a preventative solution against these parasites. When given according to the instructions, these pills prevent new flea eggs from hatching on your dog. According to Dr. Michael F. Potter, an Extension Entomologist at the University of Kentucky College of Agriculture:

“When an adult female flea bites a Program-treated dog or cat, the flea ingests the active ingredient (lufenuron) which then passes into her eggs and prevents them from hatching.” – Dr. Michael F. Potter, DVM (source)

Fleas and other parasites that attack dogs are also dangerous to humans and can have a negative impact (PDF) on our health too. Not only are humans extremely sensitive to these bites (so you'll be extremely itchy), fleas also can transmit bacteria and viruses through their saliva.

“What if my dog already has fleas?”

If your dog is already infested with fleas, see this video guide on how to remove fleas from a dog. Samantha has covered everything from preventing fleas to removing them from the dog and within the house, including the best solutions (store bought and homemade).

Ultimately, prevention is the best way to fight off fleas on dogs. So once you remove them, ensure that your pooch is protected for the future.

Many preventative measures (such as electric flea traps, flea collars, flea shampoos, flea powders, flea drops and topical flea treatments) only ward off fleas and ticks. The best flea pills for dogs will also keep your pet safe from other parasites including heartworms and intestinal parasites.

As the old saying goes, an ounce of prevention is worth a pound of cure. Don't wait until your dog is infested with fleas to take action. Research, find and purchase best flea pill for dogs products now, discuss it with your veterinarian, and prevent the flea infestation from taking place on your pet.

Prescription vs Over the Counter Flea Pills

The main difference between prescription pills and OTC flea pills is active ingredients.

Vet prescribed pills usually contain strong chemicals (as those noted above) that need to be approved for use after rigorous checks to ensure their safety. Over-the-counter dog flea pills are usually made of natural ingredients, making them less harmful. However, they may also be less effective than prescription pills and they generally do not have any scientific studies to back up their efficacy.

Most popular prescription flea pills have different active ingredients, but they are all just generic names for various insect growth regulators and inhibitors, and insecticides. This is why the prescription is necessary and you need your vet’s approval to use these pills because your dog may be fine with some insecticides but harmed by others.

Another common difference between prescription pills and over-the-counter pills is the approach to dealing with the flea issue. Prescription flea pills work as monthly preventatives and have to be taken daily long-term. Over-the-counter flea pills act fast and only stay in your dog’s system for a few days. They are short-term solutions that need to be combined with other products to provide protection.

Oral vs Topical Flea Medications

One of the biggest advantages of oral flea medications for dogs, like flea pills or chewable tablets, is that they do not leave any mess or residue on the dog like some topical flea medications do, especially flea drops and collars.

Another advantage is the time it takes for the medication to work. Flea pills and chewables will start killing fleas in a matter of hours, while some topical medications take longer to work. Also, some studies showed that oral flea medications are simply more effective than their topical counterparts.

One obvious disadvantage of flea pills is that some require a vet’s prescription and that those that don’t haven’t really been tested scientifically. Also, flea pills usually only kill adult fleas and you may have to use them in conjunction with drops to prevent new fleas from breeding. Another common issue is the fact that flea pills usually won’t keep your dog safe from ticks and other parasites.

The Best Flea Pills for Dogs

1 Capstar Fast-Acting Oral Flea Treatment

One of the best over-the-counter flea pills on the market, Capstar is available for small and large dogs in packages of 6 or 60 pills. The active ingredient in this pill is nitenpyram, a chemical that can exterminate adult fleas only 30 minutes after the treatment. However, the peak level for this pill is anywhere up to 4 hours.

Capstar Fast-Acting Oral Flea Treatment for Dogs
7,101 Reviews
Capstar Fast-Acting Oral Flea Treatment for Dogs
  • One oral tablet starts killing...
  • Tackle flea infestations fast...
  • The convenience of an oral...
  • If your pet gets re-infested...
  • Includes 6 doses for use with...

Keep in mind that this pill doesn’t kill flea eggs as effectively as it kills adult fleas, so it may be necessary to use other products in combination with Capstar pills to get completely rid of fleas. Another option is to repeat the treatment with these pills until all the eggs are hatched and ultimately killed. This is possible since it is perfectly safe to use one pill a day, especially since these pills have been FDA approved.

While these pills are pretty effective, they are not long-lasting. They will be effective only up to 24 hours, after which you will have to give your dog another pill until all the fleas are gone. Unfortunately, some dog owners reported adverse side effects and claimed that the pills made their dogs sick. My dog was fine but you may want to consult with your vet before you give your pooch these flea pills.

» PROS: FDA Approved, Effectively Kills Adult Fleas, Safe to Use Multiple Times (One Pill Per Day)

« CONS: Not Effective with Flea Eggs, Some Reports of Adverse Side-Effects


2 PetArmor 6 Count FastCaps for Dogs

Like the majority of over-the-counter dog pills, PetArmor FastCaps also have nitenpyram as the active ingredient. These pills are also FDA approved and safe to use even for pregnant and lactating dogs, as long as you choose the right pill for your dog’s weight. You can give them directly to him to swallow but it may be easier to mix them with food.

PetArmor FastCaps (nitenpyram) Oral Flea Control...
1,252 Reviews
PetArmor FastCaps (nitenpyram) Oral Flea Control...
  • When used as directed a Single...
  • Safe for use in dogs and...
  • Also safe for use in pregnant...
  • This easy-to-dose tablet...
  • No odor or messy application

These pills act quickly, only 30 minutes after you administer them to your pooch. And, like other nitenpyram-based pills, they only kill adult fleas while they are not effective against flea eggs. That means that you will have to use other products if you want to break the flea’s life cycle.

This product comes in a package of 6 pills and each pill is effective for 24 hours. However, you can give your dog a pill per day for as long as he is still infested with fleas. Unfortunately, some dog owners reported that these pills were completely ineffective and didn’t actually kill any fleas.

» PROS: FDA Approved, Effectively Kills Adult Fleas, Safe to Use Multiple Times (One Pill Per Day)

« CONS: Not Effective with Flea Eggs, Some Reports of Ineffectiveness


3 Dog MD QuickTabs Nitenpyram Flea Treatment

This is another oral flea treatment with nitenpyram as the active ingredient, which means that the pills start working only 30 minutes after ingestion. Like other dog pills with this active ingredient, the treatment lasts for 24 hours after which it is safe to give another pill to your dog if necessary.

This flea pill is also FDA approved and doesn’t interfere with any other medications. However, this treatment is only available for dogs that weigh up to 25 pounds and it can serve as a quick relief but not as a long-term solution unless it is combined with other flea treatments and measures you should take to make sure that your home is free of fleas that could get on your dog.

The reason for this lies in the fact that this pill isn’t effective when it comes to killing flea eggs. However, you can use these pills once a day as long as it is necessary, so you will have enough time to provide a safe environment without fleas while your dog receives this oral treatment. While this pill helped my dog, some dog owners claimed that it didn’t work for them.

» PROS: FDA Approved, Effectively Kills Adult Fleas, Safe to Use Multiple Times (One Pill Per Day)

« CONS: Not Effective with Flea Eggs, Some Reports of Ineffectiveness, Only Available for Dogs Up to 25 Pounds


4 CapAction Oral Dog Flea Treatment

These flea pills for dogs are also based on nitenpyram, the FDA-approved active ingredient that kills adult fleas but not flea eggs. Like other similar dog pills, these also act quickly and their effects last for 24 hours. That means that you can use one pill on a daily basis, as long as necessary.

CapAction Oral Flea Treatment Small Dog, 6ct
1,797 Reviews
CapAction Oral Flea Treatment Small Dog, 6ct
  • For Oral Use
  • Begins Working within 30...
  • Country of origin: Switzerland
  • Package Dimension: 14. 5"L x...

You can get this product for both small and large breeds, both of which come in a package with 6 pills. Since the pills are meant to provide instant relief and kill the adult fleas, they are not effective with flea eggs and you may need to combine this product with other flea treatments to completely break the life cycle of fleas that have infested your dog and your home.

When I used CapAction oral flea treatment, I have combined it with a thorough cleaning and disinfecting of all the areas of my house where fleas could remain and I have used the product for two weeks to ensure that all the flea eggs would become adult fleas. However, some dog owners haven’t had success with this product.

» PROS: FDA Approved, Effectively Kills Adult Fleas, Safe to Use Multiple Times (One Pill Per Day)

« CONS: Not Effective with Flea Eggs, Some Reports of Ineffectiveness


5 Sentry Capguard (nitenpyram) Oral Flea Tablets

Sentry Capguard Tablets has the same active ingredient as Capstar and the three other mentioned best flea pills for dogs we’ve named so far. Capguard interrupts flea infestation by killing adult fleas on your pet’s body.

SENTRY Capguard (nitenpyram) Oral Flea Control...
1,526 Reviews
SENTRY Capguard (nitenpyram) Oral Flea Control...
  • Treat Flea Infestations With...
  • Contains Nitenpyram,...
  • Kills Adult Fleas On Your Pet
  • Easy-To-Dose Tablet Format, No...
  • NADA 141-175 - Approved by...

Pets must weigh at least 2 pounds and be at least 4 weeks old to be safely given this flea treatment. This pill works within minutes from the moment your pet swallows it and continues working in the next 24 hours. Administering the pill is no hassle and leaves no mess as long as your pet is not averse to taking it.

One dose of Senty's dog flea pill kills a lot of fleas, and they start falling off in less than an hour. As in the other nitenpyram brands, you’d need a separate medication for flea eggs and possibly anti-flea sprays for fleas that are in hiding. Sentry Capguard (nitenpyram) Oral Flea Tablets would be great to use in conjunction with treatments that affect flea eggs and larvae. Since Capguard works quickly at eliminating the adult population, it hastens the work of the other treatment.

The downside of using this product alone would be the length of time that it has to be used to completely eliminate the fleas. That is so because the eggs have to be hatched and become adults first before Capguard can affect them. If you only have one pet, that may not be so difficult or expensive. With several pets, however, the cost will necessarily increase by their number, and treatment may even run to several weeks.

» PROS: The active ingredient is nitenpyram (scientifically proven to be effective), FDA approved, Starts working 30 minutes after ingestion, Works on dogs weighing more than two pounds who are more than 4 weeks old

« CONS: Only works on adult fleas, It takes longer to eliminate the infestation than other products, Can make some dogs ill


6 Flea Away All Natural Flea Repellent for Dogs

The last product on my list is completely different from all the others because it doesn’t have nitenpyram as the active ingredient. Instead, these chewable tablets are made with natural ingredients and they are made and sourced in the USA. However, the tablets were too big for my dog and I had to break them to ensure that he can swallow them.

Flea Away All Natural Flea, Tick, and Mosquito...
5,810 Reviews
Flea Away All Natural Flea, Tick, and Mosquito...
  • All natural: Flea Away is a...
  • No pesticides: Flea Away...
  • Additional benefits: our...
  • No more bites: The difference...
  • Dosage: every day, It will...

Flea Away chewables work differently than other pills I have reviewed – they prevent the infestation in the first place by making sure that your pooch emits an odor that repels fleas. In addition to this, the odor should also repel ticks and mosquitoes, which is truly a unique thing for all other flea pills for dogs. These pills have a liver flavor but they also have a strong smell that some dogs may find off-putting. However, you can mix these up with your dog’s food or use them as treats if your dog likes the taste.

Since this product is based on actually a vitamin complex and based on natural ingredients, it is completely safe for use for both dogs and even humans. One package comes with 100 tablets and your dog should build up the smell in approximately 30 days with one tablet per day dosage. Keep in mind that some reviewers claimed that these pills were ineffective but many tried using them on their flea-infested dogs. Remember, these pills should be used as prevention only and will not kill adult fleas or flea eggs – they can only help in repelling them.

» PROS: Natural Ingredients, Repel Fleas, Ticks and Mosquitoes, Tasty, Made in the USA

« CONS: Strong Smell, Tablets Too Big for Small Dogs, Some Reports of Ineffectiveness


7Four Paws Brewers Yeast Dog Flea Tablets

Similar to the above, Four Paws’ Brewers Yeast Tablets are a daily food supplement formulated to promote the overall health and wellness of your pets and protect them against flea and tick infestation.

Four Paws Brewers Yeast Garlic Flavored Dog and...
972 Reviews
Four Paws Brewers Yeast Garlic Flavored Dog and...
  • Four Paws health and wellness...
  • Natural daily supplement...
  • Excellent source of natural...
  • Includes natural proteins,...
  • Available in 4 sizes:...

It is made in the USA and uses natural and nutrient-rich ingredients like brewer’s dried yeast and garlic powder. It contains protein, biotin, and zinc to keep pets’ skin and coat healthy. There are five sizes available starting from 125-count to 2000-count.

The advantage in Four Paws Brewers Yeast Garlic Flavored Dog and Cat Tablets is clearly in its wholesomeness, there being no harmful chemicals in its ingredients list. It is highly nutritious and helps keep skin and coat healthy. This dog flea pill controls shedding and, to some degree, prevents flea and tick infestation. Giving them to your pets is also very easy because the pills look so much like treats.

Even if it's a natural choice, they’re not the best choice for treating a flea infestation in your pets though, in the same manner that our first four products were. In other words, you would not always find fallen fleas on the floor after giving your pets Four Paws’ Brewers Yeast – sometimes it works, most times it doesn't. However, if you’re thinking of a product to use in the long-term to prevent flea infestation in your pet and don't wish to use above brands, then this would be a decent and safer choice.

» PROS: Natural daily supplement, Made in the USA, Includes natural proteins, zinc, and biotin for a healthy skin and coat

« CONS: Must give 1 tablet per day for every 10 pounds of body weight, Our dogs seemed put off by the smell of these tablets and would not eat them, Doesn't always work

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