Fipronil: veterinary dose and monograph

At a glance

Drug class

Antiparasitic

Also known as

Effipro, Frontline

Species with doses

Dogs and Cats

General dose range

7.5–15 mg/kg Topical q4–8 weeks — check the species tables for the indication

Routes

Topical

Last reviewed

1 October 2026

Indications

• Adulticidal flea control (dogs and cats)
• Tick infestation control
• Sarcoptic mange (off-label, multiple applications)

Fipronil dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Flea / tick (spray): Label: 0.25% spray at 3–6 mL/kg (7.5–15 mg/kg; about 6–12 pump actions per kg depending on the pump volume), ruffling the coat to wet the skin; repeat every 4–8 weeks per label. Plumb’s 10e pp.1453–1454 (Fipronil, Topical): monthly treatment is generally recommended for fleas, ticks and chewing lice, shortened to every 14 days in some cases; spray with a gloved hand ruffling the coat until thoroughly wet; avoid shampooing for 48 hours. Not for puppies under 8 weeks. Papich 5e has no fipronil monograph.
• Sarcoptic mange (confirmed cases): Plumb’s 10e p.1454: two protocols for confirmed sarcoptic mange — weekly for 4 weeks, or every 2–3 weeks for 3 treatments; volumes of 3–39 mL/kg were used, with attention to ears, face, ventrum and extremities. Pruritus may fall within 7 days. NOT recommended for treatment trials (mites not found) — anecdotal failures.
• Cheyletiellosis (confirmed cases): Plumb’s 10e p.1454: 0.25% spray at 3 mL/kg, with environmental permethrin treatment; repeat after 30 days. Only for confirmed cases.
• Trombiculosis (chiggers): Plumb’s 10e pp.1453–1454: monthly 0.25% spray at 3–6 mL/kg throughout the trombiculid season, wetting the coat with emphasis on feet, ears, face, perineum and tail; some dogs need application every 14 days.
• Otoacariasis (ear mites): Plumb’s 10e p.1454: instil 1 drop of fipronil spot-on solution inside each ear canal and apply the rest of the tube between the shoulder blades — it must reach the ear canals to work. Signs may resolve within 7 days; additional applications may be needed.

Cats

• Flea / tick (spray): Label: 0.25% spray 3–6 mL/kg (7.5–15 mg/kg), repeated every 4–8 weeks per label. Plumb’s 10e pp.1453–1454: monthly treatment generally recommended (every 14 days in some cases); fipronil seemed shorter-acting in cats against chiggers, with reinfestation after 7–10 days. Not for kittens under 8 weeks. Use only cat-labelled products — some canine combination spot-ons contain permethrin, which is toxic to cats.

Rabbits

• CONTRAINDICATED in rabbits: Plumb’s 10e p.1454: fipronil compounds are reported to be contraindicated in rabbits, as toxicity deaths have occurred with the spray.

Contraindications

Rabbits — fatal in some cases (avoid use). Sick / debilitated / very young (<8 wk) animals — caution. Hypersensitivity. Avoid eye / mucous-membrane contact.

Species-specific warnings

Rabbits: Fipronil has caused fatalities in rabbits — avoid.

Adverse effects

• Local skin irritation / alopecia at application site
• Hypersalivation if licked
• Hypersensitivity reactions (rare)

Drug interactions

• No significant systemic drug interactions at topical doses
• Avoid concurrent topical pyrethroid (permethrin / cypermethrin): additive contact toxicity
• Bathing within 48 h of application: reduces residual efficacy (washes sebaceous reservoir)
• Sunlight: does NOT significantly degrade fipronil on coat — UV-stable

Pregnancy and lactation

Considered safe in pregnant and lactating dogs and cats at label doses. Limited systemic absorption when applied topically. Used routinely in pregnant breeding bitches and queens.

Monitoring

• Efficacy against fleas / ticks at 4–8 weeks
• Application-site reaction (alopecia, dermatitis) — switch product if persistent
• NEVER use in rabbits — verify species before dispensing
• Cat-friendly formulation — unlike pyrethroids, fipronil is SAFE for cats at label dose
• Owner education: do not bathe within 48 h of application

Toxicity and overdose

RABBITS: AVOID — fatalities reported, possibly due to formulation excipients or rapid lipid absorption. Wide therapeutic margin in dogs and cats at label doses. Topical local reaction: transient stinging, erythema, alopecia at application site. Oral ingestion (dog licks application site): hypersalivation, vomiting, ataxia at very high doses — usually self-limiting. NEVER use in pet RABBITS — recommended alternatives: selamectin or ivermectin.

Management: No specific antidote. Supportive: bathe with mild detergent for topical contamination. Activated charcoal if recent oral ingestion. IV fluids, anti-emetic, diazepam for tremors / seizures (rare). Most cases self-limit within 12–48 h. Rabbit overdose: prognosis guarded.

Clinical pearls

• Dog spot-on (Frontline Plus): 1 pipette per weight band — monthly application
• Cat spot-on: 1 pipette monthly — CAT-FRIENDLY (unlike pyrethroids)
• Spray application: 7.5–15 mg/kg topically (6–12 pumps per kg) for thorough coverage
• AVOID IN PET RABBITS — fatalities reported. Selamectin or ivermectin are safer for rabbit ectoparasites
• Do not bathe within 48 h of application — sebaceous reservoir is the source of residual activity
• Persists in coat 4–8 weeks — outperforms most pyrethroids for duration
• Combination products (with S-methoprene): also kills flea eggs/larvae for environmental control
• NOT effective for established demodicosis — use isoxazolines (afoxolaner, fluralaner) or amitraz instead

Mechanism of action

Phenylpyrazole insecticide / acaricide. IRREVERSIBLY binds and blocks GABA-gated chloride channels in arthropod neurons → hyperexcitation → death. Highly selective for ARTHROPOD GABA receptors (mammalian GABA-A receptors are much less sensitive). Effective adulticide for fleas (24 h kill), ticks (48 h kill), lice, and some mites. Persists in sebaceous glands and hair coat for 4–8 weeks after spot-on application — provides sustained protection. Active metabolite (fipronil sulfone) extends duration.

Formulations and products

• Effipro spray 0.25 % w/v (Virbac, 80 mL pump)
• Frontline Plus spot-on 9.8 % w/v
• Effipro Spray (Virbac) — 0.25 % w/v fipronil, Cutaneous spray
• Extick Spray (Pet Mankind (Mankind Pharma)) — 0.25 % w/v fipronil, Cutaneous spray

Storage

Spray / spot-on: 15–25 °C, original packaging, protect from light. Keep away from children / pets. Sealed pipettes have indefinite shelf life within expiry date.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antiparasitics

• Eprinomectin
• Epsiprantel
• Febantel
• Fenbendazole
• Flumethrin
• Fluralaner
• Halofuginone
• Imidacloprid

Frequently asked questions