Bravecto for Cats: Dosage, Safety, and Side Effects

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-09-19

Bravecto for cats is a prescription-only topical flea and tick treatment built around the active ingredient fluralaner. It is applied to the skin at the back of the neck and absorbed into the bloodstream, where it kills fleas and ticks that bite the cat. A single dose is labeled to control fleas for up to 12 weeks and ticks for 12 weeks, which makes it the only topically applied systemic ectoparasiticide approved for redosing at intervals of up to 12 weeks in cats [1][2]. It is intended for healthy cats that meet the label's minimum age and weight, and it must be obtained through a veterinarian.

This guide covers how fluralaner works, the labeled weight-band dosing, onset and duration of activity, the adverse reactions reported in cats, who should not receive the product, how it compares with monthly alternatives, and the questions worth asking a veterinarian before you start treatment.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

At a Glance

What Bravecto for Cats Is and What It Treats

Bravecto for cats is a transdermal spot-on solution containing fluralaner, a member of the isoxazoline class of parasiticides. It is labeled for the treatment and control of flea infestations and for the treatment and control of tick infestations in cats [1][2]. The product is systemic, meaning the drug crosses the skin and enters the cat's bloodstream rather than staying on the surface of the coat. Fleas and ticks are killed when they bite the cat and ingest fluralaner along with the blood meal.

The 12-week redosing interval is the defining feature of the product. Every other feline systemic ectoparasiticide on the market, including other isoxazolines, is approved for redosing at monthly intervals [2]. That difference matters for owners who struggle to keep up with monthly applications. In a survey of cat owners in the United States, the United Kingdom, and France who were treating their cats with transdermal fluralaner, the most frequently reported benefit was the 12-week dosing interval, and more than 94 percent of owners in each country were satisfied or very satisfied with the product [1].

Bravecto for cats is not a dewormer. It does not treat gastrointestinal nematodes, does not prevent heartworm disease, and does not treat tapeworms. Those jobs belong to other products. A separate formulation, fluralaner plus moxidectin, combines the flea and tick activity of fluralaner with moxidectin for nematode treatment and heartworm prevention [4][5][6]. Owners should not assume that a Bravecto product purchased for fleas and ticks also covers intestinal parasites.

How Fluralaner Works

Fluralaner is an isoxazoline. The isoxazoline class acts as an inhibitor of gamma-aminobutyric acid (GABA)-gated chloride channels and L-glutamate-gated chloride channels [7]. In plain terms, these channels control the flow of chloride ions into nerve and muscle cells, and that flow is what keeps insect and acarine nervous systems in a controlled state. When fluralaner blocks the channels, chloride cannot move normally, the parasite's nerve and muscle cells become hyperexcitable, and the flea or tick is paralyzed and dies.

This mechanism is selective for invertebrate channels. That selectivity is the reason isoxazolines have a wide margin of safety in mammals at labeled doses, and it is also why the class is effective against a broad range of external parasites. The same GABA and glutamate channel targets appear across fleas, ticks, and mites, which is why isoxazolines including fluralaner have been used in cats for conditions beyond fleas and ticks, such as feline demodicosis, although that use falls outside the label [8].

Absorption and Distribution

After topical application, fluralaner is absorbed through the skin and distributed systemically. In cats, the drug is readily absorbed from the application site into the skin, underlying tissues, and blood [9]. Absorption is slow. In one pharmacokinetic study of a fluralaner plus moxidectin spot-on formulation in healthy cats, the time to peak plasma concentration for fluralaner occurred roughly 10 to 18 days after dosing, and quantifiable concentrations were maintained throughout a 160-day sampling period [10]. A separate study reported a fluralaner time to peak concentration of 14 days with an interquartile range of 5 to 28 days [11].

That slow absorption profile explains the long duration of activity. Because the drug enters the bloodstream gradually and is eliminated slowly, plasma concentrations stay high enough to kill fleas and ticks for months rather than weeks. Fluralaner is eliminated primarily through the biliary and fecal route, with a fecal elimination half-life reported between 3 and 12 days in felids [12]. A prolonged elimination profile also means the drug persists in the body well after the labeled 12-week interval, which is relevant to any discussion of switching products or breeding cats.

Because the drug is distributed systemically rather than sitting on the hair coat, bathing and shampooing do not wash it away. In dogs, water immersion and shampooing after fluralaner spot-on application did not reduce efficacy against ticks or fleas [13]. The same systemic distribution applies to cats, which is why the label does not restrict swimming or bathing after application in the way that some surface-acting products do.

Bravecto for Cats Dosage: Labeled Weight Bands

Bravecto for cats is sold in pre-filled applicators, and each applicator is matched to a body weight band. The dose is not calculated by the owner and is not adjusted for breed, coat length, or body condition. The correct approach is to weigh the cat, select the applicator that covers that weight, and apply the entire contents of the tube.

The following table reflects the labeled weight bands for the feline topical product.

The minimum labeled dose rate for cats is 40 mg of fluralaner per kg of body weight [14][6]. The weight bands are constructed so that a cat at the low end of a band receives at least the minimum dose rate and a cat at the high end of a band does not receive an excessive dose. This is why owners should not split applicators between cats or use a large-cat applicator on a small cat to save money. Splitting a tube means neither cat receives a reliably measured dose, and the product is not formulated or packaged for that use.

How to Apply It Correctly

1. Confirm the cat's current weight and select the matching applicator.
2. Part the hair at the base of the neck, between the shoulder blades, until the skin is visible.
3. Place the tip of the applicator against the skin and squeeze the entire contents onto the skin in one spot.
4. Keep the cat from grooming the application site until it is dry. Separate treated cats from untreated cats for the first few hours so they do not groom each other.
5. Wash your hands after application and store the remaining applicators out of reach of children and pets.

Applying the product to the fur rather than the skin reduces absorption and may lower effectiveness. If you are unsure whether the full dose reached the skin, contact your veterinarian rather than applying a second dose immediately.

Onset and Duration of Activity

The labeled onset and duration data come from controlled field and laboratory studies in cats.

The flea efficacy data are strong. In a randomized, blinded, controlled field study in the United States, households with healthy cats at least 12 weeks old and weighing at least 1.2 kg were assigned to a single owner-applied fluralaner topical treatment or to three monthly treatments with fipronil/(S)-methoprene. Efficacy was assessed at weeks 4, 8, and 12, and treatment was considered effective when mean live flea counts fell by 90 percent or more and differed significantly from baseline [3]. In a simulated home environment study, a single topical fluralaner application at the labeled feline dose rate controlled fleas for 12 weeks [14].

Tick efficacy in cats has been evaluated in a European field study of a fluralaner plus moxidectin spot-on formulation. In that study, tick and flea counts were lower in the fluralaner plus moxidectin group than in the fipronil group throughout the 12-week study period, and efficacy against ticks and fleas exceeded 97 and 98 percent respectively. At 12 weeks, 94.1 percent of cats in the fluralaner plus moxidectin group were free of ticks and 93.3 percent were free of fleas [4].

The practical takeaway is that Bravecto for cats starts killing fleas quickly after they bite the cat, and a single dose keeps working for about three months. It does not repel fleas or ticks. Parasites still get on the cat, but they are killed after they attach and begin feeding. Owners who expect a repellent effect may be surprised to see a flea or tick on a treated cat, and that is not evidence of product failure. It is evidence that the flea or tick has not yet taken a blood meal and died.

Adverse Reactions and Side Effects

The adverse reaction profile of fluralaner in cats is well characterized across field studies and safety trials. Most reactions are mild and transient. The reactions owners most commonly report fall into a small number of categories.

Adverse Reaction Checklist for Owners

• Vomiting
• Diarrhea
• Lethargy or reduced activity
• Decreased appetite
• Itching, hair loss, or redness at the application site
• Dandruff-like flakes or small crusts at the application site
• Salivation, especially if the cat grooms the application site soon after treatment
• Rare neurologic signs such as tremors, unsteadiness, or abnormal behavior

What the Safety Studies Show

In a safety study of concurrent topical fluralaner plus moxidectin and praziquantel in cats, one cat out of ten in the praziquantel-only control group and two cats out of ten in the combination treatment group had dandruff-like flakes in the coat at the application site. Two control cats and three treated cats had very small amounts of unidentified material at the application site that was only visible on close inspection. No adverse findings were attributed to the combination [15].

In a safety study of concurrent fluralaner and emodepside-praziquantel, few mild and transient clinical findings were observed, including erythema at the administration site and single instances of salivation or vomiting. All of those findings were consistent with the individual product leaflets, and there was no evidence of an increased safety risk from concurrent treatment [16].

Field studies of fluralaner-containing spot-on products in naturally infested cats reported acceptable safety alongside high efficacy [4][5]. A pharmacokinetic study of a fluralaner plus moxidectin spot-on formulation in healthy cats reported no adverse reactions at the doses tested [10].

What to Do If a Reaction Occurs

Mild vomiting, soft stool, or a day of reduced activity after application usually resolves without treatment. Offer water, keep the cat comfortable, and monitor for improvement. Contact your veterinarian if vomiting or diarrhea persists beyond 24 to 48 hours, if the cat stops eating, if lethargy deepens, or if you see any neurologic sign such as tremors, wobbliness, or unusual behavior. If the cat groomed the application site and is drooling heavily, wipe the mouth and contact your veterinarian for guidance.

Signs at the application site, including redness, itching, or hair loss, are usually mild. Do not apply a second dose to the same area. If the skin reaction spreads or the cat scratches the area raw, have the cat examined.

Reporting a Suspected Reaction

In the United States, suspected adverse drug reactions can be reported to the manufacturer and to the FDA Center for Veterinary Medicine. Your veterinarian can help you file a report and can determine whether the reaction is related to the product or to another cause.

Who Should Not Receive Bravecto for Cats

Bravecto for cats is not appropriate for every cat. The label sets a minimum age and weight, and the product should not be used outside those limits.

• Kittens under 12 weeks of age. The labeled minimum age is 12 weeks [3].
• Cats weighing less than 1.2 kg (2.6 lb). The labeled minimum weight is 1.2 kg [3].
• Sick, debilitated, or underweight cats. The product has not been established as safe in these cats, and a veterinarian should assess the cat before any ectoparasiticide is used.
• Cats with a known hypersensitivity to fluralaner or to any component of the formulation.
• Breeding, pregnant, or lactating cats. The safety of fluralaner in breeding, pregnant, and lactating cats has not been established. A veterinarian should weigh the risks and benefits.

Do not use Bravecto for cats on dogs, and do not use the dog product on cats. The canine chewable and the canine topical products are formulated and dosed differently, and using a dog product in a cat can cause serious harm. If you have both species in the household, keep the products separate and read the label every time.

Off-Label Use: What Owners Should Know

Fluralaner is a prescription-only medication in the United States, and the label defines the species, age, weight, dose, and redosing interval for which the product has been evaluated. Using it outside those parameters is off-label use.

Off-label use is not automatically wrong. Veterinarians can and do prescribe medications off-label when the clinical situation calls for it, and there are published reports of isoxazolines including fluralaner being used in cats for conditions such as generalized demodicosis caused by Demodex cati, where no controlled studies exist and treatment options are limited [8]. The key point is that off-label use should be a decision made by a veterinarian who knows the cat, not a decision made by an owner based on a forum post or a friend's experience.

Risks of off-label use include dosing errors, use in animals outside the labeled age or weight range, use in pregnant or lactating cats, and use in combination with other medications that have not been evaluated together. If a veterinarian recommends fluralaner for a purpose not on the label, ask what evidence supports it, what side effects to watch for, and what the follow-up plan is.

Owners should also avoid giving any human medication to a cat. Human drugs are not dosed for feline physiology, and some common human medications are toxic to cats.

Interactions and Concurrent Treatments

Cats often receive more than one parasiticide at the same time, and owners frequently ask whether products can be combined. The available safety data are reassuring for several common combinations.

Concurrent topical administration of fluralaner plus moxidectin with a praziquantel spot-on product at the highest dose rates used in clinical practice did not produce adverse findings in a controlled safety study [15]. Concurrent topical treatment with fluralaner and an emodepside-praziquantel combination at maximum recommended dose rates produced only mild and transient findings consistent with the individual product leaflets, with no evidence of increased risk [16].

A pharmacokinetic study of a fluralaner plus moxidectin spot-on formulation found that after intravenous co-administration, fluralaner exposure increased while moxidectin exposure decreased compared with single-agent administration, indicating a potential pharmacokinetic interaction between the two compounds [10]. That finding applies to the combined product and is a reminder that drug interactions are possible even within a single formulation. It does not mean that fluralaner alone interacts with moxidectin in a way that affects the flea and tick activity of Bravecto for cats.

Because fluralaner is absorbed systemically and eliminated slowly, it remains in the body for an extended period. If a cat needs a different ectoparasiticide, or if a cat develops an adverse reaction and the veterinarian wants to change treatment, the presence of fluralaner in the bloodstream is part of the clinical picture. Tell your veterinarian about every product the cat has received in the past several months, including prescription and over-the-counter products.

How Bravecto for Cats Compares With Alternatives

Feline flea and tick control falls into a few broad categories. The choice depends on the cat's age and weight, the owner's ability to apply medication consistently, the parasites of concern, and whether the cat needs coverage for internal parasites as well.

The main practical difference between fluralaner and the monthly products is adherence. A 12-week interval means fewer applications per year and fewer opportunities to miss a dose. A study of ectoparasiticide purchase records from 671 U.S. veterinary clinics found that most cat owners bought six months or less of protection during a 12-month period, with 61 to 75 percent purchasing only one to three months of protection depending on the product [18]. A separate analysis of purchase records from 41,630 cats found that owners purchased an average of 1.5 doses of fluralaner per year, which at a 12-week redosing interval provides about 4.2 months of treatment coverage [17]. Longer intervals reduce the number of doses needed, but they do not eliminate the need for owners to refill on schedule.

Owners who want flea and tick control plus deworming and heartworm prevention may be better served by a combination product. Fluralaner plus moxidectin provides 12 weeks of flea and tick protection and also treats gastrointestinal nematode infections and prevents heartworm disease [4][5][6]. That product is not the same as Bravecto for cats, and the two should not be confused at the pharmacy.

Questions to Ask Your Veterinarian

Before starting Bravecto for cats, or any flea and tick product, ask the following.

1. Does my cat meet the label's minimum age and weight for this product?
2. Is my cat healthy enough for a systemic ectoparasiticide today?
3. Does my cat need tick coverage, or is flea control the main concern?
4. Does my cat also need deworming or heartworm prevention, and would a combination product be a better fit?
5. What side effects should I watch for, and when should I call you?
6. How should I handle other pets in the household during and after application?
7. When should I schedule the next dose, and how will I remember it?
8. If my cat has an adverse reaction, how do I report it and what is the plan for switching products?

Limitations and When to Contact a Veterinarian

This article describes labeled uses, dosing, and adverse reactions for Bravecto for cats based on published studies and label information. It cannot tell you whether this product is right for your individual cat. That decision requires a veterinarian who can examine the cat, review its history, and consider other medications and conditions.

Contact a veterinarian promptly if any of the following occur.

• Persistent vomiting or diarrhea lasting more than 24 to 48 hours
• Refusal to eat or drink
• Marked lethargy, weakness, or collapse
• Tremors, unsteadiness, or any other neurologic sign
• Facial swelling, hives, or difficulty breathing
• Severe or spreading skin reaction at the application site
• Any reaction in a kitten under 12 weeks of age or a cat under 1.2 kg
• Any reaction in a pregnant, lactating, or breeding cat
• Any suspected accidental oral exposure, such as a cat grooming the product off another cat

If you are unsure whether a sign is related to the medication, call your veterinarian. It is better to ask than to wait.

Frequently Asked Questions

How often do you apply Bravecto for cats?

Apply one dose every 12 weeks. The product is labeled for redosing at intervals of up to 12 weeks for flea and tick control in cats [1][2].

How fast does Bravecto for cats kill fleas?

It kills fleas within hours of attachment, after the flea begins feeding on the treated cat. The drug is systemic, so the flea must bite the cat to take up a lethal dose.

Does Bravecto for cats kill ticks?

Yes. It is labeled for tick control for 12 weeks after a single dose [1][2]. It does not repel ticks, so a tick may still be found on a treated cat before it dies.

What are the most common side effects of Bravecto for cats?

Vomiting, diarrhea, lethargy, decreased appetite, and application-site reactions such as redness, itching, or dandruff-like flakes. Most reactions are mild and short-lived.

Can I use Bravecto for cats on a kitten?

Only if the kitten is at least 12 weeks old and weighs at least 1.2 kg (2.6 lb) [3]. Kittens below those limits should not receive the product.

Can I use the dog Bravecto product on my cat?

No. The dog products are formulated and dosed for dogs, and using them in cats can cause serious harm. Use only the feline product that matches your cat's weight.

Can I bathe my cat after applying Bravecto?

Yes. Fluralaner is absorbed systemically, so bathing and shampooing do not wash the drug off. In dogs, water immersion and shampooing after application did not reduce flea or tick efficacy [13].

Is Bravecto for cats available over the counter?

No. It is prescription-only in the United States. A veterinarian must authorize the product after assessing the cat.

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