Pet Safety / Compounds / Fenvalerate

Is Fenvalerate safe for dogs and cats?

Low risk for pets

Dogs metabolize fenvalerate efficiently; no specific veterinary concerns at typical agricultural or household product exposure levels. Livestock animals (cattle, sheep, poultry) are also relatively tolerant; fenvalerate is registered for ear tag and dip application in livestock for fly and tick control.

What is fenvalerate?

The IUPAC name is [cyano-(3-phenoxyphenyl)methyl] 2-(4-chlorophenyl)-3-methylbutanoate.

Also known as: [cyano-(3-phenoxyphenyl)methyl] 2-(4-chlorophenyl)-3-methylbutanoate, Phenvalerate, Pydrin, Sumicidin.

IUPAC name
[cyano-(3-phenoxyphenyl)methyl] 2-(4-chlorophenyl)-3-methylbutanoate
CAS number
51630-58-1
Molecular formula
C25H22ClNO3
Molecular weight
419.9 g/mol
SMILES
CC(C)C(C1=CC=C(C=C1)Cl)C(=O)OC(C#N)C2=CC(=CC=C2)OC3=CC=CC=C3
PubChem CID
3347

Risk for dogs

Low risk

Dogs metabolize fenvalerate efficiently; no specific veterinary concerns at typical agricultural or household product exposure levels. Livestock animals (cattle, sheep, poultry) are also relatively tolerant; fenvalerate is registered for ear tag and dip application in livestock for fly and tick control.

Risk for cats

Extreme risk

Fenvalerate is a type II alpha-cyano pyrethroid with the same extreme feline toxicity profile as other type II pyrethroids; historically significant as one of the earlier synthetic pyrethroids to become commercially important (1970s); the esfenvalerate enantiomer (the active S-alpha isomer) has largely replaced racemic fenvalerate in modern products. Cats exposed to fenvalerate from agricultural runoff, treated ornamental plants, or indoor use products show rapid-onset CS syndrome (hypersalivation, choreoathetosis, seizures). Treatment: bathing, methocarbamol, cyproheptadine, supportive thermoregulation.

Regulatory consensus

2 regulatory and scientific bodies have classified Fenvalerate. The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA CTX / IARC—Group 3 - Not classifiable as to its carcinogenicity to humans
EPA CTX / EPA OPP—Group E Evidence of Non-carcinogenicity for Humans

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 fenvalerate

  • 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 Fenvalerate:

  • 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 fenvalerate safe for pets?

Dogs metabolize fenvalerate efficiently; no specific veterinary concerns at typical agricultural or household product exposure levels. Livestock animals (cattle, sheep, poultry) are also relatively tolerant; fenvalerate is registered for ear tag and dip application in livestock for fly and tick control.

What products contain fenvalerate?

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

See Fenvalerate in the pets app

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

Open in pets View raw API data

Sources (2)
  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. 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 →