Is Afoxolaner (NexGard) safe for dogs and cats?
Moderate risk for petsAfoxolaner presents a moderate risk to dogs, reflecting the FDA-required neurological adverse event warning that applies to the entire isoxazoline class. In the majority of dogs, NexGard (afoxolaner) is well-tolerated and provides effective monthly flea and tick protection. Post-marketing surveillance has identified neurological adverse events (tremors, ataxia, seizures) in a subset of treated dogs, including some without prior neurological history. Dogs with epilepsy, seizure disorders, or known neurological conditions should be treated with informed owner consent and close veterinary monitoring. The monthly dosing interval (vs. fluralaner's 12-week interval) means that if adverse effects develop, no further doses are administered and the drug is eliminated within approximately 45–60 days. Flavored chewable presentation requires secure storage to prevent accidental ingestion by dogs seeking the flavored tablet.
What is afoxolaner (nexgard)?
The IUPAC name is 4-[5-[3-chloro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl]-N-[2-oxo-2-(2,2,2-trifluoroethylamino)ethyl]naphthalene-1-carboxamide.
Also known as: 4-[5-[3-chloro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl]-N-[2-oxo-2-(2,2,2-trifluoroethylamino)ethyl]naphthalene-1-carboxamide, Afoxolaner, NEXGARD, 02L07H6D0U.
- IUPAC name
- 4-[5-[3-chloro-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-4H-1,2-oxazol-3-yl]-N-[2-oxo-2-(2,2,2-trifluoroethylamino)ethyl]naphthalene-1-carboxamide
- CAS number
- 1093861-60-9
- Molecular formula
- C26H17ClF9N3O3
- Molecular weight
- 625.9 g/mol
- SMILES
- C1C(=NOC1(C2=CC(=CC(=C2)Cl)C(F)(F)F)C(F)(F)F)C3=CC=C(C4=CC=CC=C43)C(=O)NCC(=O)NCC(F)(F)F
- PubChem CID
- 25154249
Risk for dogs
Moderate riskAfoxolaner presents a moderate risk to dogs, reflecting the FDA-required neurological adverse event warning that applies to the entire isoxazoline class. In the majority of dogs, NexGard (afoxolaner) is well-tolerated and provides effective monthly flea and tick protection. Post-marketing surveillance has identified neurological adverse events (tremors, ataxia, seizures) in a subset of treated dogs, including some without prior neurological history. Dogs with epilepsy, seizure disorders, or known neurological conditions should be treated with informed owner consent and close veterinary monitoring. The monthly dosing interval (vs. fluralaner's 12-week interval) means that if adverse effects develop, no further doses are administered and the drug is eliminated within approximately 45–60 days. Flavored chewable presentation requires secure storage to prevent accidental ingestion by dogs seeking the flavored tablet.
Regulatory consensus
1 regulatory bodyhas classified Afoxolaner (NexGard).
| Agency | Year | Classification | Notes |
|---|---|---|---|
| IARC | 2022 | Not evaluated by IARC — afoxolaner (NexGard; Boehringer Ingelheim) is an FDA/CVM-approved isoxazoline ectoparasiticide for dogs; monthly flavored chewable tablet for flea and tick prevention and treatment; FDA 2018 class-wide neurological adverse event warning (isoxazoline class); 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 afoxolaner (nexgard)
- 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 Afoxolaner (NexGard):
-
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 afoxolaner (nexgard) safe for pets?
Afoxolaner presents a moderate risk to dogs, reflecting the FDA-required neurological adverse event warning that applies to the entire isoxazoline class. In the majority of dogs, NexGard (afoxolaner) is well-tolerated and provides effective monthly flea and tick protection. Post-marketing surveillance has identified neurological adverse events (tremors, ataxia, seizures) in a subset of treated dogs, including some without prior neurological history. Dogs with epilepsy, seizure disorders, or known neurological conditions should be treated with informed owner consent and close veterinary monitoring. The monthly dosing interval (vs. fluralaner's 12-week interval) means that if adverse effects develop, no further doses are administered and the drug is eliminated within approximately 45–60 days. Flavored chewable presentation requires secure storage to prevent accidental ingestion by dogs seeking the flavored tablet.
What products contain afoxolaner (nexgard)?
Afoxolaner (NexGard) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).
See Afoxolaner (NexGard) in the pets app
Look up products containing afoxolaner (nexgard), compare to alternatives, and explore the full data record.
Open in pets View raw API dataSources (1)
- Afoxolaner NexGard Boehringer Ingelheim FDA CVM 2013; Isoxazoline GABA Chloride Channel Dog Only Monthly; FDA 2018 Class Neurological Warning Tremors Ataxia Seizures; Half-Life 14-15 Days CYP3A4 Hepatic; Beef-Flavored Chewable Flea Tick Ixodes Dermacentor Amblyomma; Post-Marketing Pharmacovigilance; EMA EU Approved; IARC Not Evaluated; Aquatic EMA VMP Assessment; NexGard Spectra Milbemycin Combination (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 →