Complete Prescription Guide & Safety Review
Guide to fluralaner (Bravecto) for dogs covering dosage, side effects, safety data, drug interactions, and cost. Vet-informed prescription reference.
What Is Fluralaner (Bravecto) and What Is It Used For?
Fluralaner is a systemic ectoparasiticide belonging to the isoxazoline drug class, marketed under the brand name Bravecto by Merck Animal Health. It is one of the most widely prescribed flea and tick preventives in veterinary medicine, with a distinctive dosing interval that sets it apart from monthly alternatives.
FDA-Approved Veterinary Uses:
- Flea treatment and prevention: Kills adult fleas (Ctenocephalides felis) and prevents flea infestations for up to 12 weeks
- Tick treatment and control: Effective against black-legged tick (Ixodes scapularis), American dog tick (Dermacentor variabilis), brown dog tick (Rhipicephalus sanguineus), and lone star tick (Amblyomma americanum) for up to 12 weeks
- Aiding in treatment and control of sarcoptic mange (Sarcoptes scabiei)
- Aiding in treatment and control of demodectic mange (Demodex canis)
Common Off-Label Uses (prescribed at veterinarian discretion):
- Ear mite (Otodectes cynotis) treatment in dogs
- Adjunct therapy in flea allergy dermatitis (FAD) management protocols
- Part of multi-modal treatment plans for tick-borne disease prevention in high-endemic areas
Bravecto is available in two formulations: a flavored chewable tablet (Bravecto Chew) and a topical solution (Bravecto Topical). A newer combination product, Bravecto Plus, adds moxidectin for heartworm and intestinal parasite coverage. The chewable tablet is the most commonly prescribed form in general practice.
How Does Fluralaner Work? Mechanism of Action
Drug Class: Isoxazoline (systemic parasiticide)
Target: Invertebrate nervous system — specifically ligand-gated chloride channels
Action: Fluralaner binds to and blocks gamma-aminobutyric acid (GABA)-gated chloride channels and glutamate-gated chloride channels in the nervous systems of fleas, ticks, and mites. This blockade causes uncontrolled neuronal hyperexcitation, leading to paralysis and death of the parasite.
The critical safety advantage of isoxazolines like fluralaner lies in their selective binding affinity. These compounds bind far more strongly to invertebrate GABA receptors than to mammalian GABA receptors. According to the Merck Veterinary Manual, the selectivity ratio is substantial enough that therapeutic doses produce parasiticidal activity without significant interference with canine neurological function in the vast majority of dogs.
Pharmacokinetics in dogs:
- Absorption: Oral bioavailability increases significantly when administered with food (fatty meal enhances absorption by approximately 2.5x compared to fasted state)
- Half-life: Approximately 15 days in dogs — this extended half-life is what enables the 12-week dosing interval
- Distribution: Distributed systemically via blood plasma; parasites are exposed when they feed on treated blood
- Metabolism: Primarily hepatic metabolism
- Elimination: Excreted mainly through feces, with minor urinary excretion
- Onset of action: Begins killing fleas within 2 hours of administration; achieves >98% flea kill within 12 hours
Typical Dosage of Bravecto by Dog Weight
Bravecto chewable tablets are dosed according to body weight bands. The target dose is approximately 25 mg/kg (11.4 mg/lb) of fluralaner per administration, given once every 12 weeks (84 days).
| Dog Weight Range | Tablet Strength | Fluralaner Content (mg) | Approx. mg/kg Dose |
|---|---|---|---|
| 4.4 – 10 lb (2 – 4.5 kg) | Bravecto 112.5 mg | 112.5 mg | 25 – 56 mg/kg |
| 10.1 – 20 lb (4.6 – 9 kg) | Bravecto 250 mg | 250 mg | 28 – 54 mg/kg |
| 20.1 – 40 lb (9.1 – 18 kg) | Bravecto 500 mg | 500 mg | 28 – 55 mg/kg |
| 40.1 – 88 lb (18.1 – 40 kg) | Bravecto 1000 mg | 1000 mg | 25 – 55 mg/kg |
| 88.1 – 123 lb (40.1 – 56 kg) | Bravecto 1400 mg | 1400 mg | 25 – 35 mg/kg |
Important dosing notes:
- Bravecto is not approved for dogs under 4.4 lb (2 kg) or puppies under 6 months of age
- The chewable tablet must be given with food or shortly after a meal for adequate absorption — administering on an empty stomach can reduce efficacy by up to 60%
- For dogs exceeding 123 lb, your veterinarian will prescribe the appropriate combination of tablets to achieve the correct dose
- For sarcoptic and demodectic mange, the same dose applies, but your veterinarian may recommend re-dosing at a shorter interval (e.g., every 8 weeks) depending on clinical response
How to Administer Bravecto: Step-by-Step Instructions
Administration protocol for Bravecto chewable tablets:
- Confirm your dog's current weight — weigh your dog on the day of dosing or within the preceding week. Weight changes can shift your dog into a different dosing band.
- Feed your dog a regular meal first. The tablet should be given with food or within 20 minutes of eating. A meal containing some fat content significantly improves absorption.
- Offer the chewable tablet. Bravecto tablets are flavored and most dogs accept them readily as a treat. If your dog refuses, you can hide the tablet in a small amount of food (cheese, peanut butter — xylitol-free only), but ensure the entire tablet is consumed.
- Do not split or crush the tablet. The tablet is formulated for intact administration. Breaking it may affect absorption consistency.
- Observe your dog for 30 minutes post-dosing. If vomiting occurs within 1-2 hours of administration, contact your veterinarian — a replacement dose may be needed.
- Record the administration date. Set a calendar reminder for 12 weeks (84 days) from the dosing date. Mark it on your phone calendar with a recurring alert.
Dosing frequency: One dose every 12 weeks for flea and tick prevention. Year-round administration is recommended in most U.S. climates, as fleas can survive indoors during winter months and ticks remain active at temperatures above 37°F (3°C).
Side Effects of Bravecto: What to Watch For
Bravecto has been administered to millions of dogs worldwide since its FDA approval in 2014. In pre-approval field studies and post-market surveillance, the majority of adverse events are mild and self-limiting. However, as with all isoxazoline-class drugs, certain neurological side effects require attention.
| Side Effect | Reported Frequency | Severity | Action Required |
|---|---|---|---|
| Vomiting | ~1.7% | Mild | Monitor; call vet if persistent |
| Decreased appetite | ~1.3% | Mild | Monitor; usually resolves in 24-48 hrs |
| Diarrhea / soft stool | ~1.2% | Mild | Monitor; ensure hydration |
| Lethargy / drowsiness | ~0.8% | Mild | Monitor; typically resolves same day |
| Flatulence | ~0.5% | Mild | No action needed |
| Skin reactions (topical form) | ~0.4% | Mild-Moderate | Contact vet if persistent irritation |
| Seizures / tremors | Rare (<0.1%) | Serious | Emergency vet visit |
| Muscle tremors / ataxia | Rare (<0.1%) | Serious | Emergency vet visit |
| Hypersalivation (excessive drooling) | Rare | Moderate-Serious | Contact vet promptly |
- Seizures (even a single episode)
- Muscle tremors or shaking that persists beyond 30 minutes
- Ataxia (stumbling, inability to walk normally, loss of coordination)
- Uncontrollable vomiting (more than 2 episodes within 4 hours)
- Facial swelling, hives, or difficulty breathing (signs of anaphylaxis)
- Complete refusal to eat for more than 24 hours post-dosing
If you suspect a severe adverse reaction, contact your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 (24/7, consultation fee applies). You can also report adverse events to the FDA through your veterinarian or directly at FDA's Safety Reporting Portal.
The isoxazoline and seizure question: In 2018, the FDA issued an advisory noting that isoxazoline-class drugs (fluralaner, afoxolaner, sarolaner, lotilaner) have been associated with neurological adverse events including muscle tremors, ataxia, and seizures in some dogs. These events are rare but can occur even in dogs without a prior seizure history. Dogs with pre-existing epilepsy or neurological conditions may be at increased risk. Your veterinarian will weigh this risk against the benefits of flea/tick protection when making prescribing decisions.
Contraindications: Dogs Who Should NOT Receive Bravecto
Bravecto is contraindicated or requires careful veterinary risk-benefit assessment in the following situations:
- Puppies under 6 months of age — safety has not been established in this age group
- Dogs under 4.4 lb (2 kg) — no approved dosage form for this weight class
- Dogs with a known history of seizure disorders (epilepsy) — not an absolute contraindication, but your veterinarian may recommend a non-isoxazoline alternative or implement closer monitoring
- Dogs with a history of adverse reaction to any isoxazoline drug (afoxolaner/NexGard, sarolaner/Simparica, lotilaner/Credelio)
- Breeding, pregnant, or lactating dogs — Bravecto has been evaluated for safety in breeding dogs and is considered safe, but your veterinarian should still be informed of reproductive status
A common misconception is that Bravecto is unsafe for herding breeds with the MDR1 gene mutation (Collies, Australian Shepherds, etc.). Current evidence does not indicate that fluralaner is a substrate for the P-glycoprotein transporter affected by MDR1 mutations. However, always inform your veterinarian of your dog's breed and any known genetic test results before starting any medication.
Drug Interactions and Concurrent Medications
| Concurrent Medication | Interaction Risk | Veterinary Guidance |
|---|---|---|
| Phenobarbital (anti-seizure) | Moderate | Phenobarbital induces hepatic enzymes and may reduce fluralaner plasma levels, potentially decreasing efficacy. Vet may adjust dosing interval or recommend alternative. |
| Potassium bromide | Low | No clinically significant interaction reported, but monitor seizure control. |
| Ivermectin (high-dose, off-label) | Low-Moderate | Both affect chloride channels theoretically. At approved heartworm-prevention doses of ivermectin (6 mcg/kg), risk is negligible. High-dose ivermectin protocols require vet oversight. |
| NSAIDs (carprofen, meloxicam, etc.) | Low | No known direct interaction. Commonly co-prescribed safely. Monitor for GI upset. |
| Other isoxazolines | High | Never combine with NexGard, Simparica, or Credelio. Duplicate therapy increases neurological side effect risk. |
| Systemic corticosteroids | Low | No direct interaction, but steroids may alter immune response to parasite die-off. |
Always provide your veterinarian with a complete medication list before Bravecto is prescribed — including supplements, over-the-counter products, and any medications recently discontinued. This is particularly important for dogs on anti-epileptic drug protocols, as the combination of seizure history and isoxazoline use requires individualized risk assessment.
Monitoring and Follow-Up Requirements
For routine flea/tick prevention in healthy dogs:
- No routine bloodwork required solely for Bravecto administration
- Annual wellness exam sufficient for ongoing prescription renewal
- Weight check at each dosing to confirm correct weight band
For dogs on Bravecto for mange treatment:
- Skin scraping at 4-week intervals to assess mite clearance
- Follow-up veterinary visit at 8-12 weeks to evaluate clinical response
- Potential re-dosing at 8-week interval if mites persist (veterinarian-directed)
- Secondary skin infection assessment — bacterial pyoderma often requires concurrent antibiotic therapy
For dogs with seizure history prescribed Bravecto:
- Seizure diary maintained by owner (frequency, duration, severity)
- Follow-up call or visit within 48-72 hours of first dose
- Neurological examination if any change in seizure pattern occurs
- Consideration of switching to non-isoxazoline class if seizure frequency increases
Cost of Bravecto and Availability
Bravecto is a prescription-only medication available through your veterinarian's office, veterinary pharmacies, and authorized online retailers (Chewy Pharmacy, 1-800-PetMeds) with a valid veterinary prescription.
| Weight Band | Single Dose (1 Chew) | Annual Cost (4 Doses) | Cost Per Month (Effective) |
|---|---|---|---|
| 4.4 – 10 lb | $45 – $55 | $180 – $220 | $15 – $18 |
| 10.1 – 20 lb | $48 – $58 | $192 – $232 | $16 – $19 |
| 20.1 – 40 lb | $52 – $62 | $208 – $248 | $17 – $21 |
| 40.1 – 88 lb | $56 – $68 | $224 – $272 | $19 – $23 |
| 88.1 – 123 lb | $62 – $75 | $248 – $300 | $21 – $25 |
Generic availability: As of 2026, no FDA-approved generic fluralaner product is available for dogs in the United States. Bravecto remains under Merck Animal Health's patent protection. Be cautious of any website claiming to sell "generic Bravecto" — these may be counterfeit products lacking proper quality control and efficacy guarantees.
Cost comparison context: When comparing to monthly alternatives, factor in the per-month effective cost. Bravecto's 12-week interval means four doses per year versus twelve for monthly products like NexGard (afoxolaner, ~$18-22/month) or Simparica Trio (~$22-28/month). The effective monthly cost of Bravecto is generally competitive or slightly lower than monthly isoxazolines, with the added convenience of fewer administrations.
Missed Dose, Overdose, and Emergency Protocols
If you miss a scheduled Bravecto dose:
- Administer the missed dose as soon as you remember, with food
- Reset your 12-week calendar from the actual administration date (not the originally scheduled date)
- During the gap in coverage, your dog may be vulnerable to flea and tick attachment — perform thorough tick checks after outdoor activity
- If the gap exceeds 4 weeks, your veterinarian may recommend a fast-acting oral flea treatment (such as nitenpyram/Capstar) as a bridge
If your dog accidentally receives an overdose (double dose or wrong weight band):
- Contact your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 immediately
- Do not induce vomiting unless directed by a veterinary professional
- Monitor closely for neurological signs (tremors, ataxia, seizures) for 24-48 hours
- In safety studies, fluralaner was administered at up to 5x the recommended dose without serious adverse effects in healthy adult dogs — but individual sensitivity varies, and veterinary guidance is essential
- Keep the product packaging available to provide exact dosage information to the veterinary team
Alternatives to Bravecto: Other Options to Discuss with Your Vet
If Bravecto is not the right fit for your dog — due to seizure history, adverse reactions, or owner preference — several alternative flea and tick preventives are available. Consult your veterinarian to determine the best option for your dog's specific health profile.
| Product | Active Ingredient | Drug Class | Dosing Interval | Formulation |
|---|---|---|---|---|
| NexGard | Afoxolaner | Isoxazoline | Monthly | Chewable |
| Simparica | Sarolaner | Isoxazoline | Monthly | Chewable |
| Credelio | Lotilaner | Isoxazoline | Monthly | Chewable |
| Frontline Plus | Fipronil + (S)-methoprene | Phenylpyrazole | Monthly | Topical |
| Seresto Collar | Imidacloprid + flumethrin | Neonicotinoid + pyrethroid | 8 months | Collar |
| Vectra 3D | Dinotefuran + pyriproxyfen + permethrin | Neonicotinoid + pyrethroid | Monthly | Topical |
Important note for households with cats: Permethrin-containing topical products (Vectra 3D, K9 Advantix) are highly toxic to cats. If you have cats in the home, discuss this with your veterinarian when selecting a dog flea/tick product, and ensure treated dogs are separated from cats until the topical application site is fully dry.
For dogs where all isoxazoline-class drugs are contraindicated, topical fipronil-based products or the Seresto collar represent non-isoxazoline alternatives, though they may have different efficacy profiles — particularly against certain tick species. Your veterinarian can advise on the most appropriate option for your geographic area's parasite pressure.
Frequently Asked Questions About Bravecto
How long does my dog need to be on Bravecto?
Bravecto is intended for year-round, ongoing parasite prevention. There is no maximum duration of use established — dogs can safely remain on Bravecto throughout their entire adult life when monitored by a veterinarian. The AKC recommends year-round flea and tick prevention for dogs in most U.S. regions. If you wish to discontinue, discuss the timing with your veterinarian to minimize parasite exposure risk.
Can I use Bravecto on my dog if they are on other medications?
In most cases, yes — Bravecto has a relatively low interaction profile. However, dogs taking phenobarbital, high-dose ivermectin, or any other isoxazoline-class drug require special consideration. Always provide your full medication list to your veterinarian before starting Bravecto.
Is Bravecto safe for dogs with epilepsy?
This is a nuanced clinical decision. The FDA advisory on isoxazolines and neurological events applies to all drugs in the class, including fluralaner. Some veterinary neurologists recommend avoiding isoxazolines in dogs with active seizure disorders, while others continue to prescribe them with enhanced monitoring when the benefit of reliable parasite protection outweighs the theoretical risk. This decision should be made between you and your veterinarian — or your veterinary neurologist — based on your dog's individual seizure frequency, severity, and geographic parasite risk.
Does Bravecto protect against heartworms?
No. Standard Bravecto (fluralaner only) does not protect against heartworms (Dirofilaria immitis). You will need a separate heartworm preventive such as ivermectin-based (Heartgard Plus), milbemycin-based (Interceptor Plus), or the combination product Bravecto Plus (fluralaner + moxidectin), which adds heartworm and intestinal parasite coverage. Your veterinarian can advise on whether a combination product or separate medications are more appropriate for your dog.
My dog vomited shortly after taking Bravecto. What should I do?
If vomiting occurs within 1-2 hours of administration, a significant portion of the dose may not have been absorbed. Contact your veterinarian — they will likely recommend re-dosing. If vomiting occurs more than 4 hours after administration, the medication has likely been sufficiently absorbed and re-dosing is generally not necessary. Always inform your vet of the timing.
Can Bravecto be used alongside a flea shampoo or flea collar?
Combining Bravecto with other flea/tick products is generally unnecessary and may increase the risk of adverse reactions without meaningfully improving efficacy. Bravecto alone provides comprehensive flea and tick coverage. If you feel your dog's protection is inadequate, consult your veterinarian before adding additional products rather than self-prescribing combinations.
This article is for informational purposes only and does not replace professional veterinary advice. Always consult your veterinarian before starting, stopping, or changing any medication for your dog. Drug information is current as of publication; formulations, labeling, and recommendations may change. Refer to the FDA Center for Veterinary Medicine and the Merck Veterinary Manual for the most current prescribing information.
Jonas Cole
All our authors care for dogs every day — read more of their work on the authors page.
