Best Flea Medicine for Dogs: Vet-Approved Options

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Fleas aren’t just annoying—they can make your dog sick, spread diseases, and be a source of major discomfort. So, choosing flea medicine for dogs with optimal protection is a pretty big deal. 

Whether your dog already has fleas or you want to prevent them, here’s the scoop on how to choose the best flea treatment for dogs. Discover the best veterinarian-approved prescription and over-the-counter options to keep infestations away.  

The Importance of Flea Medicine for Dogs

Flea bites not only cause itchiness and skin irritation, they can result in serious illness, says Dr. Jerry Klein, chief veterinary officer for the American Kennel Club.

“In tiny puppies and kittens, fleas can cause a life-threatening anemia due to significant loss of blood,” he says. “Flea bites can cause severe allergic reactions in pets and people sensitive or allergic to flea saliva.” 

Fleas can carry infectious diseases. “The most common flea of North America can transmit diseases like typhus, flea-borne spotted fever, bartonellosis (cat-scratch disease), and flea tapeworms,” Dr. Klein adds.

Preventing fleas is easier (and cheaper) than dealing with an infestation. “The longer an infestation goes untreated, the more environmental contamination occurs,” says Dr. Ashley Barnes, DVM.

“That can make resolving the infestation more difficult,” adds Dr. Barnes, who is medical director at Louisville Family Animal Hospital in Louisville, Colorado. “It also extends the pet’s discomfort and increases their risk for secondary skin infections.”

Another benefit of flea preventatives is that many offer protection against ticks that can transmit diseases like Lyme disease, Rocky Mountain spotted fever, and rickettsiosis. Some products even protect against heartworms, mites, mosquitoes, and other parasites.

Best Flea Medication for Dogs: Our Top Picks

• Best Combination Parasite Protection for Dogs: NexGard PLUS
• Best Fast-Acting Tick and Flea Medicine for Dogs: Credelio Quattro
• Best Flea Medicine for Large Dogs: NexGard
• Best Flea Medicine for Small Dogs: Simparica
• Best Vet-Recommended Flea Medicine for Dogs: Simparica Trio
• Best Chewable Flea Medicine for Dogs: Bravecto
• Best Topical Flea Medicine for Dogs: Revolution
• Best Flea Medicine for Dogs with Multi-Worm Protection: Trifexis
• Best Flea Medicine for Puppies: Revolution Topical Solution for Puppies

Types of Flea Medicine for Dogs

Flea medicine for dogs is available in a variety of forms. Pet parents can choose from oral options (chews and pills), topicals, collars, and shampoos. They range in cost, effectiveness, and levels of protection.

Oral Flea Medicine for Dogs

Oral flea medicine for dogs typically comes as a flavored chew you give your dog every one to three months. With some exceptions, oral medicine is generally available only with a prescription.

Some flea chews for dogs protect against fleas and ticks, while others offer broader coverage. For example, the prescription flea and tick medicine Simparica Trio also helps protect against heartworm disease, roundworms, and hookworms.

Capstar is an over-the-counter flea medicine that comes in tablet form. When it comes to killing fleas, it’s among the best flea pills for dogs. However, it only targets adult fleas and is only effective for a short time.

While Capstar can rid your dogs of adult fleas, it’s more of a short-term solution. When the flea eggs on your dog mature, flea infestation can easily recur.

For long-term prevention, look for preventatives that contain both growth regulators and adulticides. These work by disrupting the flea reproductive cycle.

“In really bad infestations, we will sometimes use Capstar along with a preventative so we kill the fleas faster but prevent reinfestation,” says Dr. Barnes. 

Other oral flea preventatives remain in your dog’s system for one to three months, offering continued protection.

Oral products are the most effective form of flea medicine for dogs, according to vets. They’re a good option if your dog doesn’t do well with collars. And they’re a great solution for those concerned about exposing kids or other pets to topical flea medicine ingredients.    

Oral flea medicine for dogs is generally more expensive than other products, says Dr. Susan Jeffrey, an associate veterinarian at Odyssey Veterinary Care in Fitchburg, Wisconsin.

It’s also important to note that oral flea meds don’t repel fleas. “The flea has to bite the pet in order to ingest the medication,” Dr. Jeffrey adds.

Chewable flea prevention may not be a good fit for dogs with food sensitivities or conditions like irritable bowel disease, says Dr. Klein.

Additionally, “These products should be cautioned in pets with pre-existing epilepsy,” says Dr. Katie Pagan, a partner veterinarian with Heart + Paw in Fells Point, Maryland.  

Topical Flea Protection

When it comes to flea-killing power, “Orals are more effective, but the topicals are a close second,” says Dr. Barnes.

You apply these products to your dog’s skin, typically once per month. Some topical flea medicines for dogs, like Frontline Plus, are available over the counter. Others, like Revolution, require a prescription.

They also vary in their levels of protection. Revolution, for example, protects against heartworms, as well as fleas and ticks. Advantage is only effective against fleas. 

One plus for topicals is that many repel fleas in addition to killing them, says Dr. Jeffrey. 

On the other hand, topical medications don’t just stay on your dog. They can easily transfer to other people and pets in your home.

This may be a dealbreaker if you don’t want to expose your kids to the chemicals in topical flea preventatives.

Additionally, “Some topicals also have tick preventives that can be toxic to cats” says Dr. Jeffrey. This could endanger any cats who might come into contact with the medication. 

Prescription topical medications are typically more effective, while non-prescription topicals vary in efficacy.

However, pet parents often want to know how to get the best flea medicine for dogs without vet prescription.

“If I know someone who wants an affordable over-the-counter medication, I try to steer them toward Frontline Plus or Advantage,” says Dr. Jeffrey. ” These are known to be safe and usually effective.”

Flea Collars

Once a flea collar is fitted properly around the dog’s neck, it slowly distributes ingredients that kill fleas (and ticks, in some cases). Collars are available without a prescription and are more cost-effective than chews or topicals. 

As with other over-the-counter flea products, effectiveness can vary. “A Seresto collar is very effective for dogs (and cats),” says Dr. Pagan. “However, other collars out on the market just do not work well or can cause contact dermatitis to the skin,” she adds.

The duration of protection varies by product, as well. Seresto’s collar lasts for eight months, while other brands promise only four to six months of flea protection. It’s important to note that a flea collar must make contact with your dog’s skin to work effectively,

Collars can offer protection, says Dr. Klein, but are not used as much as topicals, pills, and shampoos. 

Flea Shampoos

Most veterinarians recommend oral flea medicine, topicals, and collars for optimal protection. However, pet parents who prefer a natural product may opt for a flea shampoo. Keep in mind that shampoos don’t offer ongoing protection against fleas. “It only kills what is on them,” warns Dr. Pagan. 

As with other non-prescription flea products, not all shampoos are equally effective. And some dog shampoos can interfere with topical tick and flea medicines. Discuss using a flea shampoo with your veterinarian before bathing your dog with one of these products.

Best Flea Medicine for Dogs According to Veterinarians

To help take the guesswork out of choosing effective parasite protection, we’ve compiled a helpful guide. Below are the top flea medicines for dogs that veterinarians approve of and recommend. 

However, to answer the question,” What flea medicine is best for dogs?” always consult your veterinarian. Because your vet knows your dog best, they can recommend the best flea control for dogs based on your pet’s health and needs.

Best Combination Parasite Protection for Dogs

Our pick: NexGard PLUS

NexGard PLUS (afoxolaner, moxidectin, and pyrantel chewable tablets) is a monthly combination product for dogs. It protects against fleas, ticks, heartworm disease, roundworms, and hookworms.

By combining internal and external parasite protection in a single beef-flavored soft chew, NexGard PLUS helps make monthly dosing easier for both dogs and pet parents.

This “one-and-done” parasite protection product is available by prescription only. So talk to your veterinarian to see if it’s a good fit for you and your canine companion.

See important safety information for NexGard PLUS below.

Highlights

• From the maker of HEARTGARD Plus, one of the top vet-recommended heartworm disease preventives
• Beef-flavored monthly soft chew designed to be easy to give to dogs
• Kill adult fleas, kill ticks, prevent heartworm disease, and treat and control three species of hookworms and two species of roundworms
• Available in four strengths, according to a dog’s weight
• Approved for puppies as young as 8 weeks, weighing 4 pounds or more

Things to Consider

• Your dog should be tested for existing heartworm infection prior to starting this product
• Available by prescription only
• Most frequently reported side effects include diarrhea, vomiting, lethargy, and itching
• Use with caution in dogs with a history of seizures or neurological disorders

Best Fast-Acting Tick and Flea Medicine for Dogs

Our pick: Credelio Quattro

Credelio Quattro is the first and only monthly chewable preventative to protect against not only fleas and ticks, but also roundworms, hookworms, tapeworms, and heartworm disease.

This small chewable tablet is flavored, so it’s easy to administer once a month with food. Plus, it kills ticks and fleas fast (in as little as four hours) and offers one full month of protection.

Quattro is effective against four types of ticks: lone star tick, American dog tick, black-legged tick, and brown dog tick. This medication is available by prescription, so talk to your veterinarian about whether it is a good fit for your dog. Some pet parents may choose to use this medication along with Interceptor Plus, which protects against all five major worms, for broad-spectrum parasite protection.

Highlights

• Small, tasty chewable tablet comes in appealing beef flavor, so it’s easy to administer once a month
• Offers the broadest parasite protection, covering 6 common canine parasites
• Starts to kill fleas and ticks in just 4 hours
• Also effective against roundworms, hookworms, tapeworms, and heartworm disease
• Protection lasts a full month
• Available in a variety of strengths, according to a dog’s weight

Things to Consider

• Must be administered with food or given within 30 minutes of feeding your dog
• Cost varies depending on the strength of the dose and the number of doses in each box
• Not suitable for puppies under 8 weeks of age 
• Dogs must weigh 3.3 pounds or greater to use this medication
• Use with caution in dogs with a history of seizures or neurologic disorders

Best Flea Medicine for Large Dogs

Our Pick: NexGard

This beef-flavored chew kills adult fleas and ticks for one month. It’s FDA-approved to help prevent Lyme infections caused by black-legged ticks. 

Highlights

• Kills fleas before they can lay eggs
• FDA-approved to prevent Lyme infections from black-legged ticks
• Offers formulations designed specifically for large dogs, including those weighing between 60 and 121 pounds 
• Comes in a tasty beef-flavored chew that can be taken without food

Things to Consider

• Requires a prescription from your veterinarian
• Chewable flea and tick medicine for dogs should be used with caution in epileptic dogs
• Dogs with food allergies or sensitive stomachs may not tolerate this medication well
• Fleas have to bite the dog for the medicine to be effective

Best Flea Medicine for Small Dogs

Our Pick: Simparica

This medication comes in the form of a bite-sized flavored chew that offers protection for 35 days and is available with a prescription. It protects dogs from flea infestations and ticks, including the black-legged species. Another plus is that Simparica doesn’t need to be given with food. 

Highlights

• Kills adult fleas, prevents infestations, and kills ticks that carry Lyme disease
• Comes in formulations designed for small dogs, including those weighing between 2.8 and 5.5 pounds
• Can be given without food

Things to Consider

• Requires a prescription

Best Flea Medicine for Dogs with Multi-Worm Protection

Our pick: Trifexis

Trifexis is a beef-flavored tablet that offers prevention against a host of parasites. It not only protects dogs from fleas but also heartworm disease and three kinds of intestinal parasites: hookworms, roundworms, and whipworms.

It’s easy (and tasty!) to give like a treat and only needs one dose a month. As with other heartworm medications, your dog must be tested for an existing heartworm infection before starting this product. Talk to your veterinarian to see if Trifexis is a good fit for your canine companion.

Highlights

• Monthly, beef-flavored tablet given orally
• Kills fleas on dogs and prevents infestations
• Prevents heartworm disease
• Treats and controls hookworm, roundworm, and whipworm infections
• Full month of protection
• Available in a variety of  strengths, according to a dog’s weight

Things to Consider

• Your dog will need to be tested for an existing heartworm infection before starting this medication 
• Administer with food for maximum effectiveness
• Cost varies depending on the strength of the dose and the number of doses in each box
• Not suitable for puppies under 8 weeks of age
• Dogs must weigh 5 pounds or more to use this medication
• Potential side effects may include vomiting, decreased activity, itching, decreased appetite, and diarrhea
• If vomiting occurs within one hour of administration, you will need to redose
• Use with caution in dogs with pre-existing epilepsy

Check out our full review

Best Vet-Recommended Flea Medicine for Dogs

Our Pick: Simparica Trio

Veterinarians recommend Simparica Trio because of its effective protection against ticks and fleas, as well as heartworms, roundworms, and hookworms. All that protection comes in one, small, convenient monthly chew that’s liver-flavored and available by prescription. Because it provides heartworm protection, your dog will need a negative heartworm test on file in order to be prescribed this product. 

“I personally give this product to my dog along with hundreds of thousands of other dogs and have never had an issue,” says Dr. Pagan. 

Highlights

• Multi-purpose chew that kills fleas and prevents infestations
• Kills five types of ticks (including the Lyme-carrying black-legged tick)
• Treats and controls roundworms and hookworms
• Helps prevent heartworm disease
• Liver-flavored chew can be taken with or without food

Things to Consider

• The cost for a six-month supply (six tablets) averages between $140 to $170 dollars, depending on the size of your dog
• You can only get Simparica chewables with a prescription from your veterinarian.
• Because it contains a heartworm preventative, your dog needs a negative heartworm test on file
• As with any oral flea medication, the flea has to bite the dog in order to ingest the medicine
• May not be a good option for dogs with food sensitivities or epilepsy

Best Chewable Flea Medicine for Dogs

Our Pick: Bravecto

While most flea medications require monthly dosing, a single Bravecto chew provides protection against fleas and ticks for 3 full months. This makes it a convenient option for busy pet parents who might forget to administer a dose every month. Bravecto chews are available by prescription only.

Highlights

• Provides flea and tick protection for 3 months 
• Works within hours after dosing

Things to Consider

• Requires a prescription from your veterinarian
• Oral flea medicine for dogs may not be a good fit if your dog has epilepsy or food sensitivities
• Though one chew lasts for up to three months, it costs between $57 and $60.

Best Topical Flea Medicine for Dogs

Our Pick: Revolution

Revolution is a multi-use, FDA-approved topical solution that you apply directly to your dog’s skin every 30 days. This prescription med protects against fleas (and prevents infestations), the American dog tick, heartworms, ear mites, and sarcoptic mange.

“I personally have prescribed this countless times,” says Dr. Pagan. “It is very safe and effective.”

Highlights

• Multi-spectrum product that protects against fleas, ticks, heartworms, ear mites, and mange
• Good option for dogs who won’t eat chews or tolerate collars
• Non-greasy, quick-drying formula
• You can bathe your dog two hours after application without it affecting the ingredients

Things to Consider

• Requires a prescription from your veterinarian, as well as a negative heartworm test
• May not be a good option if you’re concerned about children or pets being exposed to flea medicine ingredients

Best Flea Medicine for Puppies

Our Pick: Revolution Topical Solution for Puppies

If you’re looking for the best canine flea treatment for puppies, here it is. Revolution Topical Solution for Puppies is formulated for pups under 5 pounds. Simply apply the solution directly to your puppy’s skin monthly.

This prescription-only, multi-use product kills adult fleas, prevents flea infestations, prevents heartworm disease, and treats and controls ear mites.

It’s also fast-drying, so you can bathe your dog two hours after application without reducing the medicine’s effectiveness. 

Highlights

• Formulated for puppies under 5 pounds
• Kills adult fleas, prevents infestations, prevents heartworm disease, and treats ear mites
• Non-greasy formula dries quickly 

Things to Consider

• Requires a prescription and heartworm test on file

Dog Flea Medicine Buying Guide

When deciding on the best flea prevention for dogs, there’s much to consider. Cost and convenience are, of course, important factors. However, it’s equally important to consider your dog’s age, size, and medical history. Plus, you need to weigh product efficacy and any potential side effects, too.  

What to Do When Purchasing a Flea Medicine

Consider your dog’s medical history. Dr. Pagan recommends caution if considering chewable tablets for dogs with epilepsy. If your dog has a sensitive stomach, she says you may want a collar or topical instead of a pill.

“If your dog is itchy and has sensitive skin a chewable tablet would be better suited for your needs,” Dr. Pagan suggests. “If you bathe your pet often and do not like a greasy product applied to the coat, a chewable tablet is for you and your pet.”  

Be careful with cats in the home. If you also share your home with cats, avoid flea and tick medicine for dogs containing permethrin, says Dr. Jeffrey.

This ingredient, common in many tick meds, is toxic to cats. “Since most flea preventives have a tick preventative, I avoid this ingredient if there is a cat in the household,” she adds.

Make sure to read the label closely. When purchasing flea medicine without a prescription, it’s crucial to thoroughly read the label. Pay close attention to whether the product is appropriate for your dog’s weight and age, says Dr. Klein.

“Many medications are not label-approved for puppies less than seven weeks of age, breeding, pregnant or nursing dogs,” he adds.  

Prescription Vs. Over the Counter Flea Medicine for Dogs

If cost is a factor, you can ask your veterinarian to recommend an affordable over-the-counter (OTC) option. However, even the best flea treatment for dogs without a vet prescription may leave your pet vulnerable to infestation.

Vets generally prefer prescription flea medicine for dogs because it’s better regulated. Prescription products also tend to be more effective than the best OTC flea treatment for dogs. Plus, there’s less risk of side effects with prescription flea preventatives.

If you do opt for OTC, shop with care. “Make sure you are purchasing any OTC products through a reputable party as there are many counterfeit products out on the market,” warns Dr. Pagan.

Dog Flea Prevention vs. Treatment

Prevention is when you give your dog flea medicine on a regular basis to prevent infestations. “But it can also mean the product has ingredients that will repel fleas,” adds Dr. Jeffrey. Treatment, she says, is when you use a product to kill fleas already known to be present on your dog. 

Most products currently on the market target both prevention and treatment, says Dr. Pagan.

“They start killing fleas within hours and prevent them after the fact,” Dr. Pagan adds. “Some pets may develop flea allergy dermatitis or parasites secondary to fleas. So additional medications may be needed.” 

Where to Buy Flea Medicine for Dogs

Purchasing flea medicine through your veterinarian is the safest option. “Your veterinarian purchases products directly through a reputable party,” says Dr. Pagan. “That ensures these products are not counterfeit and will not cause an issue with your pet.”  

If you’d rather purchase your flea medicine independently, start by asking your veterinarian to recommend trusted retailers. Or stick with established pet supply shops or online pharmacies. These services will often contact your veterinarian directly to ensure your prescription is on file and will ship the medication directly to your door. 

Our Experts

• Dr. Jerry Klein, chief veterinary officer for the American Kennel Club
• Dr. Ashley Barnes, medical director at Louisville Family Animal Hospital
• Dr. Susan Jeffrey, associate veterinarian at Odyssey Veterinary Care
• Dr. Catherine Barnette, veterinary reviewer and expert for Great Pet Care

NexGard PLUS Important Safety Information

NexGard® PLUS (afoxolaner, moxidectin, and pyrantel chewable tablets) is safe for puppies at 8 weeks, weighing 4 pounds or more. The most frequently reported adverse reactions include diarrhea, vomiting, lethargy, and itching. Use with caution in dogs with a history of seizures or neurologic disorders. Dogs should be tested for existing heartworm infection prior to starting a preventive. For more information, click here for full prescribing information.