Ascorbic Acid (Vitamin C)
Vitamin C is used to correct deficiency in species that require a dietary source. Healthy dogs and cats generally synthesize sufficient vitamin C; broad disease-prevention benefits of extra supplementation are unproven.
Ascorbic acid solutions deteriorate with exposure to air and light. Stability of a particular compounded formulation cannot be assumed from another vitamin C product.
Group
Water-soluble vitamin
Mechanism of Action
Ascorbate is a reducing cofactor for hydroxylation reactions, including collagen synthesis, and contributes to antioxidant recycling.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dietary supplementation | 100–500 mg/animal | PO | Every 24 h | Usually unnecessary in healthy animals receiving a balanced diet. |
| Adjunctive antioxidant supplementation | 500–1000 mg/animal | PO | Every 24 h | Clinical outcome benefit is uncertain; avoid unnecessary high-dose exposure. |
Cat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dietary supplementation | 100–500 mg/animal | PO | Every 24 h | Usually unnecessary in healthy animals receiving a balanced diet. |
| Adjunctive antioxidant supplementation | 125 mg/animal | PO | Every 12 h | Clinical outcome benefit is uncertain. |
Guinea pig
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dietary vitamin C provision | 10–25 mg/kg | PO | Every 24 h | Total daily vitamin C requirement for healthy adults; account for fresh food and fortified pellets. Do not rely on dosing through drinking water. |
| Pregnancy vitamin C provision | 30 mg/kg | PO | Every 24 h | Total daily dietary provision during pregnancy; growing, lactating or ill animals may require individualized additional supplementation. |
Indications
- Correction of dietary vitamin C deficiency, especially in guinea pigs.
- Selected nutritional supplementation.
- Adjunctive antioxidant treatment has been described, but clinical benefit is not established for many proposed uses.
- The injectable deficiency-treatment regimen described for guinea pigs is 16 mg/kg IM twice weekly; this nonuniform weekly schedule is retained as clinical text rather than converted to a fictitious fixed hour interval.
Contraindications
- Avoid unnecessary high exposure in animals predisposed to calcium oxalate urolithiasis.
- Renal impairment warrants caution with high-dose administration.
- Avoid supplementation in copper-associated hepatopathy because ascorbate may increase copper-mediated oxidative injury.
- High doses can interfere with some laboratory assays, including glucose testing; consider this when interpreting results in diabetic patients.
Interactions
- Acidifying effects can add to those of other urinary acidifiers.
Adverse effects
- GI upset at high oral doses.
- Increased urinary oxalate and possible oxalate urolith risk with excessive exposure.
Toxicity
Large or repeated doses can increase oxalate burden. Base supplementation on species and nutritional need; monitor urinary and renal risk in predisposed animals.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Ascorbic acid 500 mg tablet | Tablet | 500 mg / tablet | PO |
| Limcee chewable tablet Contains ascorbic acid 100 mg plus sodium ascorbate 450 mg. Mixed ingredient bases are preserved; do not treat the sodium-salt mass as additional free ascorbic acid mass. | Tablet | ascorbic acid 100 mg / tablet + sodium ascorbate 450 mg / tablet | PO |
