Active form of thyroid hormone that binds nuclear thyroid hormone receptors (TR), directly regulating gene transcription involved in metabolism, growth, and development. Does not require peripheral conversion (unlike T4/levothyroxine). Rapid onset, short half-life.
At a glance
Class
Thyroid Hormone (Triiodothyronine)
Storage
Store at room temperature, protect from light and moisture
Dosing
Used for hypothyroidism refractory to levothyroxine (T4), or when T4-to-T3 conve
Used diagnostically — T3 suppression test differentiates euthyroid sick from occ
Frequency
q8h (diagnostic test)
Safety
Total T3 levels 4–6h post-doseHeart rateBody weightClinical response
Interactions
No documented interactions.
FAQs
Frequently asked questions
›What is Liothyronine (T3)?
Liothyronine (T3) is a thyroid hormone (triiodothyronine) used in pets. Active form of thyroid hormone that binds nuclear thyroid hormone receptors (TR), directly regulating gene transcription involved in metabolism, growth, and development. Does not require peripheral conversion (unlike T4/levothyroxine). Rapid onset, short half-life.
›What is Liothyronine (T3) used for in pets?
Liothyronine (T3) is used in veterinary medicine for: Used for hypothyroidism refractory to levothyroxine (T4), or when T4-to-T3 conve; Used diagnostically — T3 suppression test differentiates euthyroid sick from occ.
›What is the Liothyronine (T3) dose for dogs?
For dogs, Liothyronine (T3) is typically dosed as follows — Used for hypothyroidism refractory to levothyroxine (T4), or when T4-to-T3 conve: 4–6 mcg/kg PO q8h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Liothyronine (T3) dose for cats?
For cats, Liothyronine (T3) is typically dosed as follows — Used diagnostically — T3 suppression test differentiates euthyroid sick from occ: undefined undefined PO q8h (diagnostic test). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Liothyronine (T3) need a prescription?
Yes. Liothyronine (T3) is a prescription medication and should only be administered under veterinary supervision.
References
References
Textbooks & handbooks
- Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
- Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
- Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
- National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
- The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/
Clinical guidelines & consensus
- Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
- American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.
Journals & peer-reviewed studies
- Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
- Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
- ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control
Regulatory & approvals
- Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/
Databases
- Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
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.
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