Ascorbic Acid (Vitamin C)
Vitamin C is an essential dietary nutrient for guinea pigs and selected other species. Most domestic mammals synthesize adequate amounts; routine supplementation is not automatically beneficial.
Group
Vitamin supplement
Mechanism of Action
Acts as a metabolic cofactor. Most dogs synthesize vitamin C; evidence does not establish benefit for cancer prevention, infection treatment or cardiovascular prevention.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dietary supplementation | 100–500 mg/animal | PO | Every 24 h | |
| Urinary acidification | 100 mg/animal | PO | Every 8 h | |
| Injectable supplementation | 250–2500 mg/animal | IM, IV | Listed as 1–10 mL of 250 mg/mL sodium ascorbate according to animal size; no size bands or acid-equivalent basis are specified. | |
| Oxidative stress adjunct | 500–1000 mg/animal | PO | Every 24 h |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Dietary supplementation | 100–500 mg/animal | PO | Every 24 h | |
| Urinary acidification | 100 mg/animal | PO | Every 8 h | |
| Injectable supplementation | 250–2500 mg/animal | IM, IV | Listed as 1–10 mL of 250 mg/mL sodium ascorbate according to animal size; no size bands or acid-equivalent basis are specified. | |
| Oxidative stress adjunct | 125 mg/animal | PO | Every 12 h | |
| Toxic methemoglobinemia adjunct | 30 mg/kg | PO | Every 6 h | Adjunct to oxygen and acetylcysteine; does not replace acetylcysteine for acetaminophen poisoning. |
| Feline infectious peritonitis – historical adjunct | 125 mg/animal | PO | Every 12 h | Historical supplementation only; efficacy against FIP is not established and this is not antiviral treatment. |
Guinea pigs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Vitamin C deficiency | 16 mg/kg | IM | Twice weekly. Exact spacing is not given and must not be represented as a uniform 84-hour interval; injection ingredient basis requires product matching. | |
| Scurvy during pregnancy | 30 mg/kg | PO | Oral alternative; parenteral route and repeat interval are not specified. | |
| Scurvy treatment | 10 mg/kg | PO | Every 24 h | Oral treatment with supportive care; injection is described only when needed without specifying injection route. Typical improvement within a week. |
| Scurvy – 50 mg/kg alternative | 50 mg/kg | PO, IM, SC | Repeat interval is not specified; match injection ingredient basis. | |
| Scurvy prevention – weight-based listing | 10–30 mg/kg | PO, SC, IM | Repeat interval is not explicit. Oral intake is preferred for routine nutritional prevention. | |
| Scurvy prevention – dietary maintenance | 15 mg/animal | PO | Every 24 h | Daily maintenance requirement following recovery; nutritional needs vary with patient condition. |
Rabbit
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Soft stools – adjunct | 100 mg/kg | PO | Every 12 h | Supportive adjunct; investigate the underlying cause. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Post-exercise replacement | 20 g/animal | PO | Every 24 h | |
| Oxidative erythrocyte injury adjunct | 10–20 g/animal | PO | Every 24 h | Adjunct for conditions such as red-maple toxicity. |
| Oxidative erythrocyte injury adjunct | 30–50 mg/kg | IV | Every 12 h | Dilute in 5–10 L compatible crystalloid; match ascorbic-acid-equivalent injectable strength. |
| Foal perinatal asphyxia adjunct | 100 mg/kg | IV | Every 24 h | Foals; supportive adjunct, not a stand-alone treatment. |
| Urinary acidification – high historical amount | 1–2 g/kg | PO | Every 24 h | Unusually high historical amount; efficacy is uncertain and this should not be substituted for the much lower fixed supplementation amount. |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Vitamin C-responsive calf dermatitis | 3 g/animal | SC | Once | One administration, with a possible second treatment; repeat timing is not specified. |
Indications
- Vitamin C deficiency and dietary supplementation.
- Urinary acidification and described oxidative-stress adjunctive use.
Contraindications
- High doses may increase oxalate urolith risk.
- Avoid in copper-associated hepatopathy because oxidative hepatic injury may worsen.
- Use high doses cautiously in diabetes or urolith-prone patients.
Interactions
- Urine acidification may reduce urinary aminoglycoside/erythromycin activity and increase quinidine elimination.
- Enhances iron absorption; with deferoxamine it may increase tissue iron toxicity, especially in cardiac disease.
Adverse effects
- Possible oxalate urolith risk at high exposure.
Toxicity
Very large doses can cause diarrhea and increase urolith risk. Maintain hydration and monitor renal and gastrointestinal signs.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Sodium ascorbate injection 250 mg/mL Amount is sodium ascorbate; no conversion to ascorbic acid is implied. | Injection | 250 mg / mL | IM, IV |
| Xon CE ascorbic acid 500 mg tablet | Tablet | 500 mg / tablet | PO |
| Ascorbic acid 250 mg tablet | Tablet | 250 mg / tablet | PO |
| Ascorbic acid 1000 mg tablet | Tablet | 1000 mg / tablet | PO |
| Ascorbic acid 1500 mg tablet | Tablet | 1500 mg / tablet | PO |
| Ascorbic acid 100 mg/mL oral liquid | Oral Liquid | 100 mg / mL | PO |
| Ascorbic acid injection 500 mg/mL Ascorbic-acid ingredient basis; do not equate with sodium-ascorbate mass. | Injection | 500 mg / mL | IV |
Monitoring and Administration
Routine supplementation is generally unnecessary with a balanced diet in animals capable of synthesis. Increasing oral dose does not produce proportionate blood-level increases.
Protect from air and light because oxidation causes darkening and decomposition. Injectable vials may develop pressure; refrigeration can reduce this.
Sodium ascorbate injection is described at 250 mg/mL. Without an explicit ascorbic-acid equivalence, it must not be converted using an ascorbic-acid ingredient basis. Large-animal supplementation described without a named species is 1–10 mL IM or IV daily as needed, or 1–2 g PO daily; it is not assigned to guessed species.
Large-animal injectable listing uses the described 250 mg/mL product: 1–10 mL (250–2500 mg sodium ascorbate) IM or IV, repeated daily as needed. Oral listing is 1–2 g daily; no particular large-animal species is identified.
Sodium ascorbate does not acidify urine. Efficacy of ascorbic acid for urinary acidification is uncertain. High doses may cause false-negative urine glucose and stool occult-blood tests, or lower measured serum bilirubin; tell the laboratory about treatment.
Guinea-pig alternatives include 25–50 mg per animal parenterally daily until improvement, but no injection route is specified. Water supplementation uses 200 mg per litre dechlorinated water; actual intake and vitamin degradation affect delivery.