Drug Guide

Generic Name

Cyanocobalamin

Brand Names Redisol, Berubigen, Rubramin Pc, Vi-twel, Rubivite, Nascobal, Calomist, Vibisone, Ruvite, Betalin 12, Cobavite, Dodex

Classification

Therapeutic: Vitamin supplement, Mineral supplement

Pharmacological: Water-soluble B vitamin (Vitamin B12)

FDA Approved Indications

Vitamin B12 deficiency
Pernicious anemia
Other megaloblastic anemias due to vitamin B12 deficiency

Mechanism of Action

Cyanocobalamin is converted in the body to active forms of vitamin B12, which are essential coenzymes in DNA synthesis, fatty acid metabolism, and amino acid metabolism. It supports erythropoiesis and neural function.

Dosage and Administration

Adult: Dose varies by indication; typically 100-1000 mcg IM, deep SC, or IV once a day or weekly depending on severity and response.

Pediatric: Dose varies; typically 1-25 mcg IM or SC daily for deficiency, adjusted per age and weight.

Geriatric: Adjust for absorption and comorbidities; usual doses similar to adult, monitor for absorption issues.

Renal Impairment: Use with caution; dose adjustments may be necessary, especially for parenteral forms.

Hepatic Impairment: No specific adjustments typically required.

Pharmacokinetics

Absorption: Absorbed in the terminal ileum via intrinsic factor-mediated endocytosis; some absorption occurs passively.

Distribution: Wide distribution in body tissues, especially the liver, kidneys, brain, and other tissues.

Metabolism: Converted to active coenzymes MM and 5-deoxyadenosylcobalamin.

Excretion: Excreted mainly in the urine as unchanged vitamin B12 or metabolites.

Half Life: Approximately 6 days (may vary).

Contraindications

Hypersensitivity to cyanocobalamin or other cobalamins.

Precautions

Leber's disease (a hereditary optic nerve atrophy).
Consider monitoring for hypokalemia during correction of deficiency.
Use cautiously in patients with cobalt sensitivity.

Adverse Reactions - Common

Injection site pain (Uncommon)
Headache (Uncommon)
Rash (Uncommon)

Adverse Reactions - Serious

Hypersensitivity reactions, including anaphylaxis (Rare)
Blood clots or embolism (with high doses) (Rare)

Drug-Drug Interactions

Chloramphenicol (may interfere with DNA synthesis; monitor for anemia relapse).
Probenecid (may impair renal absorption).
Metformin (may impair absorption).

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor B12 levels, hematologic response, neurological status.

Diagnoses:

Risk for ineffective tissue perfusion
Imbalanced nutrition: less than body requirements

Implementation: Administer as prescribed, intramuscularly or intranasally. Watch for hypersensitivity.

Evaluation: Assess for improvement in anemia, neurological symptoms, and overall vitamin B12 levels.

Patient/Family Teaching

Explain the purpose of vitamin B12 supplementation.
Report signs of allergic reactions such as rash, itching, swelling, dizziness, or difficulty breathing.
Note that injections may be given IM, SC, or nasal as prescribed.
Maintain follow-up appointments for blood tests.

Special Considerations

Black Box Warnings: N/A

Genetic Factors: Individuals with Leber's disease should avoid cyanocobalamin due to risk of optic nerve atrophy.

Lab Test Interference: May interfere with some lab tests, including serum methylmalonic acid and homocysteine levels.

Overdose Management

Signs/Symptoms: Typically none; high doses are generally well tolerated but may cause hypokalemia or allergic reactions.

Treatment: Supportive care. Discontinue dosing if adverse reactions occur.

Storage and Handling

Storage: Store vials at room temperature (15-30°C). Protect from light.

Stability: Stable until the expiration date on the package when stored properly.