Lufenuron
Benzoylphenylurea derivative (CGA-184699)
Also known as: Program · Sentinel · CGA-184699
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Control of flea populations | See the label directions for Program with Capstar for using lufenuron with nitenpyram | PO | monthly | — | 🌎 NA |
| Adjunctive therapy for dermatophytosis | 50-100 mg/kg PO once every 14 days for two treatments, then once a month until at least two negative fungal cultures are obtained | PO | q14d then monthly | Until at least two negative fungal cultures are obtained | 🌎 NA |
- Control of flea populations: Must be given with a full meal
- Adjunctive therapy for dermatophytosis: Efficacy is considered doubtful by modern standards
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Control of flea populations | See the label directions Program and Program with Capstar for using lufenuron with or without nitenpyram | PO | monthly | — | 🌎 NA |
| Adjunctive therapy for dermatophytosis | 50-100 mg/kg PO once every 14 days for two treatments, then once a month until at least two negative fungal cultures are obtained | PO | q14d then monthly | Until at least two negative fungal cultures are obtained | 🌎 NA |
- Control of flea populations: Cats require a substantially higher oral dosage per kg than dogs for equivalent efficacy. Must be given with a full meal.
- Adjunctive therapy for dermatophytosis: Efficacy is considered doubtful by modern standards
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| E. cuniculi infections / Flea control | 30 mg/kg PO every month | PO | monthly | — | 🌎 NA |
- E. cuniculi infections / Flea control: Rabbits
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Lufenuron is an insect development inhibitor (IDI) primarily used for the control of flea populations in dogs and cats. It is highly lipophilic and acts systemically after oral or subcutaneous administration.
Key Clinical Points:
- Flea Control: Highly effective at breaking the flea life cycle, but does not kill adult fleas. It is often combined with adulticides (e.g., nitenpyram, milbemycin) for comprehensive parasite control.
- Lag Period: Because it only affects eggs and molting larvae, there is a lag period of 60-90 days before the environmental flea population is significantly reduced.
- Alternative Uses: Historically proposed as an adjunctive treatment for dermatophytosis (fungal infections) and Encephalitozoon cuniculi in rabbits, though modern veterinary consensus considers its efficacy for these indications to be highly doubtful.
- Safety: Exceptionally safe in mammals due to the lack of chitin in mammalian biology.
Mechanism of action
Lufenuron acts by inhibiting chitin synthesis, polymerization, and deposition in insects.
- Mechanism: It is believed to cause nonspecific inhibition of chitin synthesis related to serine protease inhibition.
- Effect on Fleas: When an adult female flea feeds on a treated animal, she ingests lufenuron. The drug is deposited into her eggs, preventing the development of the exoskeleton and the "egg tooth" needed for hatching. → Eggs fail to hatch or larvae die during the molting process.
- Fungal/Parasitic Theory: The theoretical basis for its use against fungi and E. cuniculi is that these organisms also contain chitin in their cell walls, though clinical efficacy has not been proven.
Safety & warnings
Contraindications
- The cat-labeled injectable product should NOT be used in dogs (severe local reactions are possible)
Adverse effects
- Vomiting
- Lethargy or depression
- Pruritus or urticaria
- Diarrhea
- Dyspnea
- Anorexia
- Reddened skin
- Small lump at injection site (cats receiving injectable formulation)
Precautions
Administration Warning: Oral lufenuron must be given with or immediately after a full, fatty meal to ensure adequate absorption.
Species Warning: Do not use the 6-month feline injectable formulation in dogs due to the risk of severe local tissue reactions.
Expectation Management: Owners must be warned that lufenuron does not kill adult fleas. Untreated animals in the same environment will perpetuate the flea life cycle.
Monitoring
- Efficacy (reduction in flea population over 60-90 days)
- Fungal cultures (if used for dermatophytosis)
Pharmacokinetics
Absorption
Approximately 40% of an oral dose is absorbed. Absorption is significantly enhanced when administered in conjunction with or immediately after (within 30 minutes) a full, fatty meal. Absorbed in the small intestine.
Distribution
Highly lipophilic; stored in adipose tissue which acts as a depot reservoir to slowly redistribute the drug back into circulation. Concentrates in the milk of lactating animals (without ill effects to nursing offspring). After SC injection in cats, 2-3 weeks are required to attain effective blood concentrations.
Metabolism
The drug is apparently not metabolized.
Elimination
Excreted unchanged into the bile and eliminated in the feces. The unabsorbed oral fraction (approx 60%) is also eliminated in feces.
Overdose
Lufenuron has a very wide margin of safety. Growing puppies dosed at levels up to 30X the recommended dose for 10 months showed no overt effects on growth or viability. Cats receiving oral dosages up to 17X the recommended dose were apparently unaffected.
Available products
Formulations
- Oral suspension
- Oral tablets (Flavor Tabs)
- Injectable suspension (6-month duration, cats only)
- Combination tablets (with milbemycin oxime and/or nitenpyram)
Veterinary
- Lufenuron Oral Suspension: 135 mg, 270 mg (Program Suspension)
- Lufenuron 6 Month Injectable for Cats: 100 mg/mL in 0.4 mL and 0.8 mL prefilled syringes (Program 6 Month Injectable)
- Lufenuron Oral Flavor Tabs: 45 mg, 90 mg, 204.9 mg, 409.8 mg (Program Flavor Tabs)
- Lufenuron and Nitenpyram Oral Tablets (Program Flavor Tabs and Capstar Flea Management System)
- Milbemycin/Lufenuron Oral Tablets with Nitenpyram (Sentinel Flavor Tabs with Capstar)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets and suspension at room temperature (15-30°C). Intermittent exposure outside this range for less than 48 hours should not affect potency. Expiration dates after manufacture: Lufenuron tablets (4 years), suspension (3 years), Sentinel tablets (3 years). Opened pouches of the oral suspension should not be stored for the next dosing cycle.
Client information
Crucial Administration Step: You must give this medication with a full meal (preferably containing some fat). If given on an empty stomach, the body will not absorb it properly, and it will not work.
- How it works: This drug is like "birth control" for fleas. It does not kill the adult fleas currently jumping on your pet, but it stops their eggs from hatching.
- Patience is key: It may take 2 to 3 months to see a complete reduction in the flea population in your home. You may need a separate medication to kill the adult fleas in the meantime.
- Treat all pets: Every dog and cat in the household must be on flea prevention, or the flea life cycle will continue.
- Missed doses: Must be used every 30 days to maximize efficacy. If a dose is missed, give it as soon as you remember and resume the monthly schedule.
- Vomiting: If your pet vomits within 2 hours of taking the pill, they will need to be re-dosed.
- Do not split tablets.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.