Pet Safety / Compounds / Etofenprox

Is Etofenprox safe for dogs and cats?

Low risk for pets

Dogs metabolize etofenprox efficiently; it is approved in some markets for dog flea and tick products. The lower overall mammalian toxicity of etofenprox compared to ester pyrethroids provides an additional safety margin in dogs. No specific concerns at registered product use concentrations.

What is etofenprox?

The IUPAC name is 1-ethoxy-4-[2-methyl-1-[(3-phenoxyphenyl)methoxy]propan-2-yl]benzene.

Also known as: 1-ethoxy-4-[2-methyl-1-[(3-phenoxyphenyl)methoxy]propan-2-yl]benzene, Ethofenprox, 1-((2-(4-Ethoxyphenyl)-2-methylpropoxy)methyl)-3-phenoxybenzene, Ethophenprox.

IUPAC name
1-ethoxy-4-[2-methyl-1-[(3-phenoxyphenyl)methoxy]propan-2-yl]benzene
CAS number
80844-07-1
Molecular formula
C25H28O3
Molecular weight
376.5 g/mol
SMILES
CCOC1=CC=C(C=C1)C(C)(C)COCC2=CC(=CC=C2)OC3=CC=CC=C3
PubChem CID
71245

Risk for dogs

Low risk

Dogs metabolize etofenprox efficiently; it is approved in some markets for dog flea and tick products. The lower overall mammalian toxicity of etofenprox compared to ester pyrethroids provides an additional safety margin in dogs. No specific concerns at registered product use concentrations.

Risk for cats

Moderate risk

Etofenprox is a non-ester pyrethroid with type I sodium channel mechanism — cats are less sensitive to etofenprox than to true ester pyrethroids due to its different metabolism (not dependent on esterase hydrolysis that is already deficient in cats, but rather on other hepatic oxidative pathways). Clinical reports suggest etofenprox causes less severe toxicosis in cats than permethrin or cypermethrin at equivalent exposures; some Japanese cat flea formulations use etofenprox for this reason. However, the compound is not benign in cats — T-syndrome tremors and ataxia have been reported; the risk classification reflects meaningful but less extreme sensitivity compared to ester pyrethroids. Cat owners should still avoid exposing cats to etofenprox products intended for other uses, and should consult a veterinarian if exposure occurs.

Regulatory consensus

1 regulatory bodyhas classified Etofenprox.

AgencyYearClassificationNotes
EPA CTX / EPA OPP—Not Likely to be Carcinogenic to Humans at Doses that Do Not Alter Rat Thyroid Hormone Homeostasis

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where pets encounter etofenprox

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Etofenprox:

  • Physical/mechanical pest control (IPM)
    Trade-offs: More labor-intensive. May not be sufficient for severe infestations.
    Relative cost: 1.2-2×

Frequently asked questions

Is etofenprox safe for pets?

Dogs metabolize etofenprox efficiently; it is approved in some markets for dog flea and tick products. The lower overall mammalian toxicity of etofenprox compared to ester pyrethroids provides an additional safety margin in dogs. No specific concerns at registered product use concentrations.

What products contain etofenprox?

Etofenprox appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).

See Etofenprox in the pets app

Look up products containing etofenprox, compare to alternatives, and explore the full data record.

Open in pets View raw API data

Sources (3)
  1. US EPA Pyrethroid Reregistration Eligibility Decision — cypermethrin/deltamethrin/lambda-cyhalothrin/bifenthrin/cyfluthrin/fenvalerate/tau-fluvalinate/fenpropathrin; type I/II classification; aquatic toxicity; cat sensitivity; sodium channel mechanism; human paresthesia; buffer zones (2011) (2011) — regulatory
  2. WHO Pesticide Evaluation Scheme (WHOPES): Etofenprox — evaluation for indoor residual spraying; long-lasting insecticidal nets; vector resistance management; mammalian safety; aquatic risk relative to ester pyrethroids; rice paddy use; non-ester pyrethroid classification (2012) (2012) — regulatory
  3. ASPCA Animal Poison Control Center: Pyrethroid Toxicosis in Cats and Dogs — type I vs type II CS/T syndromes; extreme cat sensitivity (sodium channel/UGT deficiency); bathing decontamination; methocarbamol tremor control; cyproheptadine; lipid emulsion severe cases (2023) (2023) — veterinary

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →