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Thiamine (Vitamin B1)

Water-Soluble Vitamin / Neurological Support
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Formulations
3

Mechanism of action

Essential cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase — key enzymes in glucose metabolism and the pentose phosphate pathway. Deficiency causes polioencephalomalacia (PEM) and Wernicke's encephalopathy.

At a glance

Class
Water-Soluble Vitamin / Neurological Support
Schedule
OTC
Storage
Store at room temperature; protect from light; injectable stable at room temperature

Dosing

🐕

Dog

Thiamine deficiency from raw fish diet (thiaminase enzyme), sulfite preservative
Dose
10–20 mg/kg
Route
IV, IM, SQ, PO
Frequency
q24h
🐈

Cat

Thiamine deficiency more common in cats fed raw fish diet or canned fish heavy d
Dose
50–250 mg/cat
Route
IV, IM, PO
Frequency
q24h
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 →

Formulations

💊

Other — 3

Strength
Strength
Strength

Storage

Store at room temperature; protect from light; injectable stable at room temperature

Safety

Monitoring parameters

Neurological improvement within 24–48h of treatmentDietary history correctionSerum thiamine levels if available
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

Thiamine HCl
Betaxin

FAQs

Frequently asked questions

What is Thiamine (Vitamin B1)?
Thiamine (Vitamin B1) is a water-soluble vitamin / neurological support used in pets. Essential cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase — key enzymes in glucose metabolism and the pentose phosphate pathway. Deficiency causes polioencephalomalacia (PEM) and Wernicke's encephalopathy.
What is Thiamine (Vitamin B1) used for in pets?
Thiamine (Vitamin B1) is used in veterinary medicine for: Thiamine deficiency from raw fish diet (thiaminase enzyme), sulfite preservative; Thiamine deficiency more common in cats fed raw fish diet or canned fish heavy d.
What is the Thiamine (Vitamin B1) dose for dogs?
For dogs, Thiamine (Vitamin B1) is typically dosed as follows — Thiamine deficiency from raw fish diet (thiaminase enzyme), sulfite preservative: 10–20 mg/kg IV/IM/SQ/PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Thiamine (Vitamin B1) dose for cats?
For cats, Thiamine (Vitamin B1) is typically dosed as follows — Thiamine deficiency more common in cats fed raw fish diet or canned fish heavy d: 50–250 mg/cat IV/IM/PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Thiamine (Vitamin B1) need a prescription?
Thiamine (Vitamin B1) is available over the counter. Even so, you should consult your veterinarian before giving any medication to your pet.
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
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