Best Flea Medicine For Dogs

Flea infestation is a common issue among dog owners. These high-jumping and fast-moving critters not only cause intense itchiness and discomfort to their hosts, but they also serve as conduits for other diseases.

There are worms and protozoan parasites that utilize fleas as their intermediate hosts and are transmitted to the animal’s body through flea saliva. The tiny wounds caused by their bite may serve as openings that bacteria can enter, complicating the situation. Parasitic and bacterial infections can affect the different systems of the body, leading to discomfort at best, and death at worst.

It’s not just your dog that will be affected, but everyone in your home. Fleas are not particularly picky about their food, and if the opportunity to taste human blood presents itself, they will take it.

Now that we’ve established just how important it is to keep your pet flea-free, the question remains: How to do it?

Environmental Control Of Fleas

To get rid of fleas once and for all requires more than just treatment of the animal. While this article focuses on medications to be used on pets, it is important to stress that environmental control is just as essential.

Adult fleas are on the animal, but their eggs and larva may drop from the fur and settle into the furniture and floor. Even if you get rid of the fleas on your dog, reinfection will occur when the fleas in the environment mature.

Vacuuming the rooms your dog frequents removes the eggs and larva. Don’t forget the nooks and crannies of the furniture and room as they may be deposited there. Washing your dog’s beddings and any cushions or rugs she likes to sleep on is also important. Use hot, soapy water as this effectively kills fleas at different life stages.

There are a number of flea pesticides that can be used in the home. Make sure to follow package instructions to protect humans and pets from ingesting, inhaling, or touching toxic residues.

Anti-Flea Medications

The growing number of fur parents concerned about the cleanliness and safety of their dogs has spurred the development of the ectoparasiticide market. These medications target the most common external parasites of dogs and cats, including fleas and ticks.

There are many products, many formulations, and many forms. It’s a dizzying array, but you should pick one on the basis of your dog’s medical condition, activities, and age. Note that there is always a risk of side effects when applying pesticides on your dog, but you can minimize this by consulting your veterinarian what products to buy and following manufacturer instructions.

Without further ado, we list of the most popular and well-regarded medications in the industry.

Best Anti-Flea Topical Treatments

Topical treatments have dominated the ectoparasiticide industry for decades.

  • Effective on fleas of all life stages. Topical treatments work upon contact. Whether it’s an adult flea, eggs, or larva, as long as it touches the topical treatment, it will eventually die.
  • Protects against flea-borne diseases. Because new fleas are killed before they have a chance to bite, their disease-laden saliva is not transmitted to your dog.

However, the downsides include:

  • Toxicity. Many topical medicines are toxic to both humans and pets if they are accidentally ingested, inhaled, or rubbed against mucous membranes of the body. Animals treated with these drugs should be in isolation for a couple of hours until it has been completely absorbed. When administering these medications, you should use gloves and other equipment to minimize accidental contact. Always follow package instructions and keep in a safe, dry place away from children and pets.
  • May be less effective. A study conducted in flea-infested dogs for 90 days found that topical treatments get rid of 88.4% effective, low when compared to the 99.9% effectivity of oral treatments. Factors that may have contributed to this include improper administration and lessened amount of drug in the skin over time due to wiping off over time or bathing.

Fipronil + S-methoprene (Frontline Plus For Dogs)

Frontline Plus is a widely-used spot-on treatment that contains the insect-paralyzing ingredient fipronil and insect growth regulator S-methoprene. This double whammy treatment kills adult fleas and stops the development of its immature stages.

This formulation is squeezed out between the shoulders of the dog where the risk of getting licked off is low. The fur must be parted, and the liquid must be deposited on the skin itself. The product is deposited in one spot, but it spreads across the body surface within 24 hours. It is concentrated in the oil glands and is slowly released over a period of 30 days.

This is effective against all stages of fleas, ticks, and chewing lice. It works quickly, with fleas starting to fall off within 4-8 hours of administration. It should only be applied every 30 days.

This product is formulated to stay on the skin because it can cause serious side effects if absorbed into the bloodstream. Care should be taken to make sure it does not come in contact with the mucous membranes in the mouth and eyes of both humans and animals.

Pyrethrins + Nylar + MGK 264 (Advantage Treatment Spray For Dogs)

Advantage Treatment Spray provides kill-upon-contact effectivity with a combination of three active ingredients. Pyrethrins are chemicals derived from chrysanthemum flowers. These natural compounds target the nervous system of insects and have been used to kill pests for centuries. The second active ingredient is an insect growth regulator that stops immature stages from developing into adults. The third active ingredient is a synergist, a compound that increases the efficacy of pyrethrins.

To use this product, spray it all over your dog’s body until damp, while keeping a hand over the eyes to prevent contact. To apply on the face, spray on a gloved hand and rub gently into the fur between the eyes and around the mouth. Remember not to let the spray touch mucous membranes or any bodily openings.

This product should be reapplied no less than seven days from last use. It is a handy tool for when you and your dog are taking a trip outdoors where the possibility of fleas infection is high.

Imidacloprid + Flumethrin (Seresto Collar)

Seresto is among the top choices vets recommend in the impregnated collars division. What looks like a simple yet stylish collar is actually an innovative product designed to protect your dog against external parasites. It is loaded with imidacloprid that targets fleas and lice, and flumethrin that targets mites and ticks. The polymer matrix material allows slow release over the next eight months.

That’s right, just slip the collar on and rest easy that your dog has a high level of protection for the more than half a year. Studies show that throughout this period, it is able to sustain an above 90% efficacy against common external parasites, reaching 100% in some species.

It may hurt your wallet at first, but if you divide the cost by the duration of effectivity, it comes out as a pretty economical choice. Your dog will have to wear it continuously for the next eight months, but it’s built to last, even through baths and other activities.

Best Anti-Flea Oral Medications

Orally-administered anti-flea medications have gained popularity in recent years and it’s easy to see why:

  • Targets all adult fleas on the body. The drug is administered orally and then absorbed into the bloodstream. When a flea takes a bite out of your dog, it is also ingesting poison. The effect of the drug is distributed all over the body and not just where it has been administered.
  • Selectivity. Oral medications are formulated to take advantage of the differences between a flea’s body and a dog’s body. It targets structures that are found in the former and not in the latter. This way, side effects can be minimized.
  • Long-lasting effects. The drug does its magic from inside the animal’s body, and so it cannot be washed off after baths or get wiped off over time. Its effect lasts for one month or longer, depending on the brand.
  • Ease of administration. Pharmaceutical companies understand the plight of so many dog parents out there who resort to wily means just to get their dog to take their medicine. Most oral medications are chewable tablets that meat-flavored. Believe me, your dog won’t need much coaxing to take this pill.

However, the major downside to oral medications is:

  • Little to no protection against flea-born diseases. The flea needs to ingest a certain amount of the drug to die. Depending on the drug, it can take anywhere from 2-4 hours of sucking your dog’s blood for the flea to get paralyzed. In this time, saliva and whatever helminth or protozoan parasites are in it have already been transmitted. It has no repellent abilities, so it cannot stop a flea from piggybacking on your dog.
  • Does not work on eggs or larva. Eggs and larva do not bite, hence they are not affected by oral medications.

Isoxazoline Drugs (Nexgard Spectra And Bravecto)

When isoxazoline drugs were introduced in the last decade, they revolutionized the ectoparasiticide industry. There was a fear that oral formulations that contained toxins for fleas would also cause toxicity in the dog ingesting it.

But isoxazolines work by selective binding to the GABA-receptors of the parasite’s nerve cells, with little to no effect on mammalian nerve cells. After a sufficient amount of the drug collects in the flea’s body, the flea’s nervous system becomes overstimulated, with the end result being paralysis. Unable to feed or move, the flea ultimately dies.

While a vast majority of dogs report no serious side effects when given isoxazoline drugs, there have been some reports on the development of neurological symptoms. There are no studies yet showing its safety for use in breeding animals and lactating dogs. The FDA released a statement stressing the importance of consulting a veterinarian before administering this drug class to minimize the occurrence of adverse reactions.

Afoxolaner + milbemycin oxime (Nexgard Spectra chew) boasts that it is the “most complete parasite protection in one monthly chew” and has the evidence to back it up. Afoxolaner targets external parasites, while milbemycin oxime takes care of internal parasites. That’s right, it’s anti-flea, anti-tick, anti-helminth, and heartworm preventive all rolled into one. Now that’s a lot of bang for your buck! Studies have shown that afoxolaner can kill 100% of fleas attached to a dog within 6 hours, 100% of fleas in 24 hours, and can be used to treat common mite infections in dogs. It must be given once a month for sustained protection.

Fluralaner (Bravecto chew) was among the first isoxazoline drugs to be sold on the market to protect against fleas and ticks. Its main selling point is its duration of effect: you only need one tablet every three months. Studies show that it maintains nearly 100% efficacy throughout the 12-week period. Spend on four tablets and you’ve got year-round protection from ticks and fleas!

Nitenpyram (Capstar Tablets)

The active ingredient of Capstar is a member of the neonicotinoid class of drugs. It works by irreversibly binding to the nicotinic acetylcholine receptors of fleas, with no effect on those receptors found in mammals. It results in paralysis and eventual death of the parasite.

Nitenpyram only works on fleas, but it does so extremely quickly and effectively. In thirty minutes, you will see fleas begin to fall off your dog. If your dog suffers from heavy infestation which could not be eradicated in a single dose, it is safe to give another after 24 hours.

This is used more for immediate eradication of moderate to heavy infections rather than prevention because its effects only last for a day. It is often used in conjunction with more long-acting treatments.


When you look at flea control products, there are pros and cons to each. There is no one product that can solve your dog’s woes, so the best way to keep your dog protected from flea infestation and their associated diseases is by combining oral and topical treatments.

Both oral and topical treatments work at exterminating fleas already attached to your dog. For fleas who just joined the bandwagon that is your canine buddy, topical treatments are there to kill upon contact. However, they may not be well-distributed throughout the body. This is where oral treatments come in. They take care of the fleas that have somehow gotten past the defenses of the topical treatment because of distribution in the blood.

While we have listed the most recommended flea control methods here, this guide is still no substitute for veterinary advice. They will discuss the products to use, how to use them, and when to use them to maximize efficacy and minimize the risk inherent to flea control.

Vets are in the best position to assess your dog’s load and risk of infection, medical history, life stage, and activities, and use this to come up with a holistic and safe plan to keep your dog happy, healthy, and flea-free.

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Regina Ranada

Regina graduated with a degree in Psychology and worked in Human Resources for four years before she decided to pursue her dream of becoming a veterinarian. She is interested in companion animals and wildlife medicine. She sidelines as the social media manager of her pitbull, Pablo.

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