Pet Safety / Compounds / Sarolaner (Simparica)

Is Sarolaner (Simparica) safe for dogs and cats?

Moderate risk for pets

Sarolaner presents a moderate risk to dogs due to the isoxazoline class FDA neurological adverse event warning (tremors, ataxia, seizures documented in post-marketing surveillance). In most dogs, Simparica/Simparica TRIO is well-tolerated and provides excellent comprehensive monthly parasite protection. Dogs with pre-existing epilepsy or seizure disorders face higher risk and should only receive isoxazolines with informed owner consent and close monitoring. For Simparica TRIO, the milbemycin component also triggers MDR1/ABCB1 breed caution — herding breeds with confirmed MDR1 −/− status should be assessed carefully; at the milbemycin dose in TRIO (0.5 mg/kg), the safety margin is generally adequate for MDR1 +/− heterozygotes but homozygous dogs may be at risk. The 11–12-day half-life means adverse events may persist for 2–3 weeks after dosing.

What is sarolaner (simparica)?

The IUPAC name is 1-[6-[(5S)-5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl]spiro[1H-2-benzofuran-3,3'-azetidine]-1'-yl]-2-methylsulfonylethanone.

Also known as: 1-[6-[(5S)-5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl]spiro[1H-2-benzofuran-3,3'-azetidine]-1'-yl]-2-methylsulfonylethanone, Sarolaner, Simparica, PF-6450567.

IUPAC name
1-[6-[(5S)-5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl]spiro[1H-2-benzofuran-3,3'-azetidine]-1'-yl]-2-methylsulfonylethanone
CAS number
1398609-39-6
Molecular formula
C23H18Cl2F4N2O5S
Molecular weight
581.4 g/mol
SMILES
CS(=O)(=O)CC(=O)N1CC2(C1)C3=C(CO2)C=C(C=C3)C4=NOC(C4)(C5=CC(=C(C(=C5)Cl)F)Cl)C(F)(F)F
PubChem CID
73169092

Risk for dogs

Moderate risk

Sarolaner presents a moderate risk to dogs due to the isoxazoline class FDA neurological adverse event warning (tremors, ataxia, seizures documented in post-marketing surveillance). In most dogs, Simparica/Simparica TRIO is well-tolerated and provides excellent comprehensive monthly parasite protection. Dogs with pre-existing epilepsy or seizure disorders face higher risk and should only receive isoxazolines with informed owner consent and close monitoring. For Simparica TRIO, the milbemycin component also triggers MDR1/ABCB1 breed caution — herding breeds with confirmed MDR1 −/− status should be assessed carefully; at the milbemycin dose in TRIO (0.5 mg/kg), the safety margin is generally adequate for MDR1 +/− heterozygotes but homozygous dogs may be at risk. The 11–12-day half-life means adverse events may persist for 2–3 weeks after dosing.

Regulatory consensus

1 regulatory bodyhas classified Sarolaner (Simparica).

AgencyYearClassificationNotes
IARC2022Not evaluated by IARC — sarolaner (Simparica, Simparica TRIO; Zoetis) is an FDA/CVM-approved isoxazoline ectoparasiticide for dogs; monthly oral tablet providing flea and tick protection; FDA 2018/2022 class-wide neurological adverse event warning; Simparica TRIO combines sarolaner with milbemycin oxime and pyrantel; no carcinogenicity classification

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 sarolaner (simparica)

  • Industrial FacilitiesManufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational EnvironmentsFactories, Warehouses, Transportation vehicles

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Sarolaner (Simparica):

  • Alternative drug class; Non-pharmacological therapy; Lowest effective dose
    Trade-offs: Direct chemical substitution requires verification that the replacement does not introduce new hazards (regrettable substitution). Conduct full hazard assessment of proposed alternative before adoption.
    Relative cost: 1.2-2×

Frequently asked questions

Is sarolaner (simparica) safe for pets?

Sarolaner presents a moderate risk to dogs due to the isoxazoline class FDA neurological adverse event warning (tremors, ataxia, seizures documented in post-marketing surveillance). In most dogs, Simparica/Simparica TRIO is well-tolerated and provides excellent comprehensive monthly parasite protection. Dogs with pre-existing epilepsy or seizure disorders face higher risk and should only receive isoxazolines with informed owner consent and close monitoring. For Simparica TRIO, the milbemycin component also triggers MDR1/ABCB1 breed caution — herding breeds with confirmed MDR1 −/− status should be assessed carefully; at the milbemycin dose in TRIO (0.5 mg/kg), the safety margin is generally adequate for MDR1 +/− heterozygotes but homozygous dogs may be at risk. The 11–12-day half-life means adverse events may persist for 2–3 weeks after dosing.

What products contain sarolaner (simparica)?

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

See Sarolaner (Simparica) in the pets app

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Sources (1)

  1. Sarolaner Simparica Simparica TRIO Zoetis FDA CVM 2016; Isoxazoline GluCl GABA Channel Dog; Triple Combination Milbemycin Oxime Pyrantel Heartworm Flea Tick; FDA 2018 2022 Class Warning Neurological Tremors Ataxia Seizures; Half-Life 11-12 Days 99.9% Protein Binding; MDR1 Milbemycin Component TRIO; EMA VMP Environmental Risk Aquatic Arthropod; Simparica TRIO Comprehensive Monthly Prevention; IARC Not Evaluated (2022) — regulatory

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 →