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Ergocalciferol (Vitamin D2)

Prescription
Vitamin D Supplement
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Formulations
2

Mechanism of action

Plant-derived vitamin D2 that undergoes hepatic 25-hydroxylation then renal 1-alpha hydroxylation to form active 1,25-dihydroxyvitamin D2. Promotes intestinal calcium and phosphorus absorption and bone mineralization. Less potent than calcitriol but longer-acting.

At a glance

Class
Vitamin D Supplement
Schedule
Prescription
Storage
Store at room temperature, protect from light

Dosing

🐕

Dog

Used for hypoparathyroidism and nutritional vitamin D deficiency
Dose
4000–6000 IU/kg
Route
PO
Frequency
q24h
🐈

Cat

Same as dogs
Dose
4000–6000 IU/kg
Route
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 — 2

Strength
Strength

Storage

Store at room temperature, protect from light

Safety

Monitoring parameters

Serum calcium (ionized) weekly initially then monthlyPhosphorusBUN/creatinineUrine calcium:creatinine ratio
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

Drisdol
Calciferol

FAQs

Frequently asked questions

What is Ergocalciferol (Vitamin D2)?
Ergocalciferol (Vitamin D2) is a vitamin d supplement used in pets. Plant-derived vitamin D2 that undergoes hepatic 25-hydroxylation then renal 1-alpha hydroxylation to form active 1,25-dihydroxyvitamin D2. Promotes intestinal calcium and phosphorus absorption and bone mineralization. Less potent than calcitriol but longer-acting.
What is Ergocalciferol (Vitamin D2) used for in pets?
Ergocalciferol (Vitamin D2) is used in veterinary medicine for: Used for hypoparathyroidism and nutritional vitamin D deficiency; Same as dogs.
What is the Ergocalciferol (Vitamin D2) dose for dogs?
For dogs, Ergocalciferol (Vitamin D2) is typically dosed as follows — Used for hypoparathyroidism and nutritional vitamin D deficiency: 4000–6000 IU/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Ergocalciferol (Vitamin D2) dose for cats?
For cats, Ergocalciferol (Vitamin D2) is typically dosed as follows — Same as dogs: 4000–6000 IU/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Ergocalciferol (Vitamin D2) need a prescription?
Yes. Ergocalciferol (Vitamin D2) 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
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