Cyanocobalamin (Vitamin B12)
Cyanocobalamin
Also known as: Cyanoject · Rubesol · Crysti · Crystamine · Amtech Vitamin B12 · Anivit B12 · Cobalaplex · Cyanocobalamin PXN-B12 · Neo-Cytamen · Vitbee · cobalamins · cyanocobalamine · cyanocobalaminum · cobamin · cianokobalaminas · cianocobalamina · cycobemin · Hydroxocobalamin
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cobalamin deficiency in dogs with severe GI disease (protein losing enteropathies, inflammatory bowel disease) | 25 micrograms/kg | SC/IM | once per week for 4-6 weeks, then once monthly thereafter | Lifelong therapy may be required | 🌎 NA |
| Cobalamin deficiency associated with GI disease | 250-1200 micrograms (total dose) | SC | once weekly for 6 weeks, then every 14 days for 6 weeks, then one dose 30 days later | Initial 16-week protocol | 🌎 NA |
| Cobalamin deficiency associated with exocrine pancreatic insufficiency | 250-500 mcg (total dose) | parenterally | repeat treatment based upon serum levels | — | 🌎 NA |
- Cobalamin deficiency in dogs with severe GI disease (protein losing enteropathies, inflammatory bowel disease): May take as long as 3-4 weeks to see a response.
- Cobalamin deficiency associated with GI disease: Based on body size. Recheck serum cobalamin concentration one month after last dose. If normal, continue at least monthly. If subnormal, continue weekly or bi-weekly.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cobalamin deficiency in cats with IBD | 250-500 micrograms (total dose per cat) | SC | once per week for 6 weeks, then every 1-2 months | — | 🌎 NA |
| Adjunctive treatment of idiopathic hepatic lipidosis | 250 micrograms (total dose) | SC | once per week | 6 weeks | 🌎 NA |
| Cobalamin deficiency associated with GI disease | 150-250 micrograms (total dose) | SC | once weekly for 6 weeks, then every 14 days for 6 weeks, then one dose 30 days later | Initial 16-week protocol | 🌎 NA |
| Cobalamin deficiency associated with exocrine pancreatic insufficiency | 100-250 micrograms (total dose) | SC | once weekly | — | 🌎 NA |
- Adjunctive treatment of idiopathic hepatic lipidosis: Recheck serum B12 level in one to two weeks after cessation of treatment as some cats may need repeated administration.
- Cobalamin deficiency associated with GI disease: Based on body size. Recheck serum cobalamin concentration one month after last dose.
- Cobalamin deficiency associated with exocrine pancreatic insufficiency: Periodically assess cobalamin and folate levels.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Vitamin B12 deficiency | 1-2 mL of a 1000 micrograms/mL injection (1000-2000 micrograms per horse) | IM or SC | once or twice weekly | — | 🌎 NA |
- Vitamin B12 deficiency: Dosage may be repeated as indicated by condition or response.
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of vitamin B12 deficiency associated with cobalt deficiency | 0.2-0.4 mL of a 5000 micrograms/mL injection (1000-2000 micrograms) | IM or SC | weekly intervals if necessary | — | 🌎 NA |
Swine
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Vitamin B12 deficiency | 0.1-0.4 mL of a 5000 micro-grams/mL injection (500-2000 micrograms) | IM or SC | weekly intervals if necessary | — | 🌎 NA |
Sheep
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of vitamin B12 deficiency associated with cobalt deficiency (Lambs) | 100 micrograms (total dose) | injection | once weekly | — | 🌎 NA |
| Treatment of vitamin B12 deficiency associated with cobalt deficiency (Adult sheep) | 300 micrograms (total dose) | injection | once weekly | — | 🌎 NA |
| Treatment of vitamin B12 deficiency associated with cobalt deficiency | 0.2-0.4 mL of a 5000 micrograms/mL injection (1000-2000 micrograms) | IM or SC | weekly intervals if necessary | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Cyanocobalamin (Vitamin B12) is a water-soluble vitamin essential for normal cellular function, particularly in rapidly dividing cells.
- Primary Use: Parenteral treatment of Vitamin B12 deficiency.
- Common Causes of Deficiency: Exocrine pancreatic insufficiency (EPI), inflammatory bowel disease (IBD), and other malabsorptive gastrointestinal diseases.
- Species Specifics:
- Dogs & Cats: High prevalence of deficiency secondary to GI/pancreatic disease. Giant Schnauzers (and other breeds like Beagles and Border Collies) may have a genetic defect affecting cobalamin-intrinsic factor complex absorption (Imerslund-Gräsbeck syndrome).
- Ruminants: Deficiency is often secondary to dietary cobalt deficiency, as rumen microflora require cobalt to synthesize B12.
Clinical Pearl: Unlike humans, dogs and cats lack the cobalamin-binding protein TC1. This means they can rapidly deplete their B12 stores in just 1-2 months during states of malabsorption, whereas humans take 1-2 years.
Mechanism of action
Vitamin B12 acts as a crucial coenzyme for two major enzymatic pathways:
- Methylmalonyl-CoA mutase: Converts methylmalonyl-CoA → succinyl-CoA. (Deficiency leads to methylmalonic acidemia/aciduria).
- Methionine synthase: Catalyzes the remethylation of homocysteine → methionine, which is intimately linked with folate metabolism.
- Required for normal cell growth, nucleoprotein and myelin synthesis, amino acid metabolism, and erythropoiesis.
- Note: B12 deficiency can cause a functional folate deficiency. Unlike humans, macrocytic anemias do not appear to be a significant component of cobalamin deficiency in dogs or cats.
Safety & warnings
Contraindications
- Hypersensitivity to cyanocobalamin or hydroxocobalamin
- Known hypersensitivity to cobalt or cobalamin
Adverse effects
- Pain at injection site (uncommon)
- Anaphylaxis (rarely reported in humans)
- Pain or stinging at the injection site
- Mild allergic reactions (rare)
Precautions
Safe to use during pregnancy and nursing. Serum samples to be analyzed for cobalamin and/or folate should be protected from bright light and excessive heat.
Drug interactions
Concurrent use can cause falsely low serum or red blood cell cobalamin values if a microbiologic method assay is used.
May decrease oral absorption of Vitamin B12 by altering gastric pH
Monitoring
- Serum cobalamin levels
- Serum folate status (both before and after treatment)
- Clinical signs associated with deficiency (weight loss, poor haircoat, vomiting, diarrhea)
- CBC (baseline and ongoing if abnormal)
- Serum cobalamin (Vitamin B12) levels
- Serum folate levels
- Clinical signs of gastrointestinal disease (weight gain, fecal consistency)
Pharmacokinetics
Half-life
Absorption
Cobalamin in food binds to haptocorrin in the stomach → degraded by pancreatic proteases in the duodenum → binds to Intrinsic Factor (IF) (produced in stomach/pancreas in dogs, pancreas only in cats) → absorbed in the small intestine via cubulin → enters portal circulation.
Distribution
Binds to transcobalamin 2 (TCII) for entry into target cells. Dogs and cats lack cobalamin-binding protein TC1, leading to rapid depletion of stores (1-2 months) compared to humans (1-2 years).
Metabolism
Undergoes entero-hepatic recirculation.
Elimination
Rapidly excreted into the bile.
Overdose
Cyanocobalamin is very safe. An inadvertent overdose given via SC or IM injection is unlikely to cause significant morbidity.
Available products
Formulations
- Injection
- Oral tablets (human-labeled, not recommended for small animal deficiency states)
- Injectable: 0.25 mg/ml solution
- Injectable: 1 mg/ml solution
- Oral: 0.5 mg capsule
Veterinary
- Cyanocobalamin (Vitamin B12) Injection 1000 micrograms/mL
- Cyanocobalamin (Vitamin B12) Injection 3000 micrograms/mL
- Cyanocobalamin (Vitamin B12) Injection 5000 micrograms/mL
- Anivit B12 250
- Anivit B12 1000
- Cobalaplex
- Cyanocobalamin PXN-B12
- Vitbee 250
- Vitbee 1000
Human-labeled
- Cyanocobalamin Injection 100 micrograms/mL
- Cyanocobalamin Injection 1000 micrograms/mL
- Oral tablets (not recommended for small animal deficiency states)
- Neo-Cytamen (hydroxocobalamin)
Regulatory status
Classified as POM-VPS in the UK.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store below 40°C; protect from light and freezing. Cyanocobalamin injection is reportedly compatible with all commonly used intravenous fluids.
Client information
- Patience is Key: It may take several weeks of therapy before you see noticeable improvement in your pet's condition (e.g., weight gain, improved stool quality).
- Long-term Commitment: Depending on the underlying disease (like chronic GI issues or EPI), your pet may require life-long Vitamin B12 supplementation.
- At-Home Administration: Because the medication is given as a subcutaneous (under the skin) injection, your veterinarian can teach you how to safely administer these injections at home.
Important: Even if you are giving injections at home, regular follow-up visits and blood tests are essential to ensure the B12 levels are adequately maintained.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.