Vetdrugs 2.0
Drug library

Permethrin

Pyrethroid ectoparasiticide

Permethrin

Permethrin is a synthetic pyrethroid insecticide and acaricide used in species-specific external parasite products. Canine preparations target fleas, ticks or biting vectors, while livestock products cover selected flies, lice, mites or other ectoparasites. Repellent and contact-killing effects contribute to its role in parasite and vector-exposure control.

Group

Pyrethroid ectoparasiticide

Mechanism of Action

Permethrin delays closure of arthropod voltage-gated sodium channels and prolongs sodium influx during neuronal excitation. Repetitive discharge leads to impaired coordination, paralysis and parasite death. Contact irritant and repellent effects can reduce feeding by susceptible biting insects. The duration and spectrum of activity depend on the delivery system and the exposed parasite.

Dose Rates

Dogs

Use / stageDoseRouteScheduleInstructions
Flea, tick and biting-insect controlReference onlyTOPICALOnceDo not use in: Cats, Puppies under 7 weeks, Dogs below 1.5 kg; Advantix: use the complete size-matched pipette. At 1.5–4 kg, one 0.4 mL pipette contains 40 mg imidacloprid plus 200 mg permethrin; puppies must be at least 7 weeks. Retreatment and duration depend on parasite and exposure. Never apply to cats.

Indications

Contraindications

Interactions

Adverse effects

Toxicity

Feline exposure is an emergency. Remove product from skin, control tremors and temperature and provide supportive care.

Preparations

PreparationFormStrengthRoute
Advantix 40 mg + 200 mg spot-on
Whole 0.4 mL pipette for eligible dogs 1.5–4 kg. Contains permethrin cis:trans 40:60. Not for cats; do not use as a free-volume single-active preparation.
Otherpermethrin 200 mg / 0.4 mL + imidacloprid 40 mg / 0.4 mLTOPICAL

Monitoring and Administration

Keep cats away from treated dogs until the application site is dry. Do not let cats groom treated dogs.

Use the exact complete pipette for body weight, on intact skin. Product combinations are not generic single-active dose calculations.

Advantix 40 mg + 200 mg contains 0.4 mL and is for dogs 1.5–4 kg that are at least 7 weeks old. Larger dogs require their corresponding product size.

Avoid surface-water exposure for at least 48 hours after Advantix treatment.

Permethrin is also present in livestock pour-ons, dusts and sprays for flies, lice, mites, mosquitoes, ticks and keds; these are not interchangeable with dog spot-ons. Avoid eyes and mucous membranes and wear gloves when applying.

Do not extrapolate a dose between a 45% spot-on, shampoo, dilute spray or imidacloprid combination; use the complete actual formulation and host instructions.

Veterinary use

For veterinary reference. Confirm the indication, dose, route, interval, product strength and any applicable withdrawal period before administration.