Derived from Saccharopolyspora spinosa fermentation. Activates nicotinic acetylcholine receptors at a unique site, causing involuntary muscle contractions, paralysis, and death of fleas. Also activates GABA receptors at high concentrations.
At a glance
Class
Spinosyn Insecticide
Storage
Store at room temperature below 30°C
Dosing
FDA-approved oral flea treatment
FDA-approved for cats ≥14 weeks and ≥1
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Safety
Flea burden assessmentGI tolerance (first dose)Seizure history
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Interactions
No documented interactions.
Brands
Other markets
Trifexis (with milbemycin)
FAQs
Frequently asked questions
›What is Spinosad?
Spinosad is a spinosyn insecticide used in pets. Derived from Saccharopolyspora spinosa fermentation. Activates nicotinic acetylcholine receptors at a unique site, causing involuntary muscle contractions, paralysis, and death of fleas. Also activates GABA receptors at high concentrations.
›What is Spinosad used for in pets?
Spinosad is used in veterinary medicine for: FDA-approved oral flea treatment; FDA-approved for cats ≥14 weeks and ≥1.
›What is the Spinosad dose for dogs?
For dogs, Spinosad is typically dosed as follows — FDA-approved oral flea treatment: 30 mg/kg PO Monthly. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Spinosad dose for cats?
For cats, Spinosad is typically dosed as follows — FDA-approved for cats ≥14 weeks and ≥1: 50 mg/kg PO Monthly. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Spinosad need a prescription?
Yes. Spinosad is a prescription medication and should only be administered under veterinary supervision.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →References
References
The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.
Textbooks & handbooks — 5
- Plumb's Veterinary Drug Handbook
- Withrow & MacEwen's Small Animal Clinical Oncology
- Merck Veterinary Manual
- NRC Nutrient Requirements of Dogs and Cats
- Veterinary Pharmacology and Therapeutics (Riviere & Papich)
Clinical guidelines & consensus — 4
- ASPCA Animal Poison Control Center Guidelines
- AAHA Diabetes Management Guidelines
- ASPCA Poison Control Guidelines
- RECOVER CPR Guidelines
Journals & peer-reviewed studies — 2
- EPIC Study (J Vet Intern Med 2016)
- JVIM FAT CAT Study
Regulatory & approvals — 1
- CDSCO Veterinary Drug Approval Registry (1969–2026)
Databases — 1
- Washington State University VCPL MDR1 Database