Levothyroxine Sodium Dosing for Dogs, Cats, Horses By Weight
Important Safety Information
Dosage should be adjusted based on therapeutic monitoring and individual animal response.
For horses using oral powder: 1 level teaspoon contains 12 mg, 1 tablespoon contains 36 mg of levothyroxine.
Reference Source
Saunders Handbook of VETERINARY DRUGS, Page 472-474
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Standard Dosage Guidelines
Small Animal Dosage
| Species | Route | Dosage | Frequency |
|---|---|---|---|
| Dogs | PO | 0.018-0.022 mg/kg | q12h (adjust via monitoring) |
| PO (Alternative) | 0.5 mg/m² | - | |
| IV | 0.004-0.005 mg/kg | q12h as needed | |
| Cats | PO | 0.01-0.02 mg/kg | Once daily (adjust via monitoring) |
Large Animal Dosage
| Species | Route | Dosage | Frequency |
|---|---|---|---|
| Horses | PO | 0.01-0.06 mg/kg | q24h |
| PO | 0.005-0.03 mg/kg | q12h |
Additional Information
Equine Powder Dosing: 1 level teaspoon contains 12 mg of levothyroxine (T₄), 1 tablespoon contains 36 mg of levothyroxine (T₄).
PPID Horses: 0.1 mg/kg (48 mg per horse) per day.
Equine Powders: Equisyn-T4, Levo-Powder, Thyroid Powder, Thyro-L.