What is Fipronil-S-Methoprene used for?

Fipronil-S-Methoprene is indicated for: Fleas and ticks.

Which species have cited Fipronil-S-Methoprene dosing data?

Fipronil-S-Methoprene dosing in the ExoticRx formulary covers 2 species: Cat (Domestic), Dog (Domestic).

Is Fipronil-S-Methoprene a controlled substance?

Fipronil-S-Methoprene is not federally scheduled in the US. Controlled-drug status differs by country — verify your local rules.

What are the warnings or contraindications for Fipronil-S-Methoprene?

Dogs and cats. Monthly topical. TOXIC to rabbits. Do not use on rabbits. Keep away from aquatic environments. Apply to dry skin.

What are the side effects of Fipronil-S-Methoprene?

Reported side effects, adverse reactions, and contraindications for Fipronil-S-Methoprene: Dogs and cats. Monthly topical. TOXIC to rabbits. Do not use on rabbits. Keep away from aquatic environments. Apply to dry skin.

Fipronil-S-Methoprene

US brand names:Frontline Plus

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Contraindicated in Rabbit

Rabbit: Fipronil causes neurotoxicosis in rabbits and is not licensed for themFipronil (Frontline and similar spot-ons) is associated with anorexia, lethargy, seizures and death in rabbits, and is explicitly not licensed for them. Never apply fipronil to rabbits; use imidacloprid or selamectin for ectoparasites. Outcome is not uniformly fatal — the cited report describes two rabbits that recovered within 24 hours of decontamination and supportive care after accidental exposure — so treat a known exposure as an emergency to be managed, not a lost cause.

Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.

Drug Class

Antiparasitic

Routes

Mechanism of Action

Fipronil blocks GABA-gated chloride channels in arthropod CNS; S-methoprene is an insect growth regulator (IGR) preventing flea egg/larval development.

Backed by a published source

· Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1481 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.1481' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.1454; verified by finding the drug named there. If you are holding the book, turn to p.1454. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207

Sample dosing (2 of 2 cited rules)

A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.

Species	Route	Dose	Frequency	Evidence	Source
Cat (Domestic)	TOPICAL	Do not use dog product on cats	q30 days	Strong	Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1481 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.1481' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.1454; verified by finding the drug named there. If you are holding the book, turn to p.1454. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207
Dog (Domestic)	TOPICAL	TOXIC to rabbits	q30 days	Strong	Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1481 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.1481' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.1454; verified by finding the drug named there. If you are holding the book, turn to p.1454. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207,

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Fipronil-S-Methoprene

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Fipronil-S-Methoprene dosing data (2 dose rules)

Evidence levels across 2 dose rules

Backed by a published source

Sample dosing (2 of 2 cited rules)

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Fipronil-S-Methoprene

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Fipronil-S-Methoprene dosing data (2 dose rules)

Evidence levels across 2 dose rules

Backed by a published source

Sample dosing (2 of 2 cited rules)

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