Pronunciation:

(sye an oh koe BAL a min)

U.S. Brand Names:

Synonyms:

Generic Available:

Canadian Brand Names:

Use:

Pregnancy Risk Factor:

Lactation:

Contraindications:

Warnings/Precautions:

Adverse Reactions:

>10%:

Cardiovascular: Peripheral vascular disease

Central nervous system: Headache (2% to 11%)

1% to 10%:

Central nervous system: Anxiety, dizziness, pain, nervousness, hypoesthesia

Dermatologic: Itching

Gastrointestinal: Sore throat, nausea and vomiting, dyspepsia, diarrhea

Neuromuscular & skeletal: Weakness (1% to 4%), back pain, arthritis, myalgia, paresthesia, abnormal gait, incoordination

Respiratory: Dyspnea, rhinitis

Miscellaneous: Infection

Frequency not defined: Peripheral vascular thrombosis, urticaria, anaphylaxis, CHF, pulmonary edema, polycythemia vera, transient exanthema

Drug Interactions:

Ethanol/Nutrition/Herb Interactions:

Stability:

Compatibility:

Y-site administration: Compatible: Heparin, hydrocortisone sodium succinate, potassium chloride, vitamin B complex with C

Compatibility when admixed: Compatible: Ascorbic acid injection, chloramphenicol, metaraminol, vitamin B complex with C. Incompatible Chlorpromazine, phytonadione, prochlorperazine edisylate, warfarin

Mechanism of Action:

Pharmacodynamics/Kinetics:

Absorption: Oral: Variable from the terminal ileum; requires the presence of calcium and gastric "intrinsic factor" to transfer the compound across the intestinal mucosa

Distribution: Principally stored in the liver and bone marrow, also stored in the kidneys and adrenals

Protein binding: To transcobalamin II

Metabolism: Converted in tissues to active coenzymes, methylcobalamin and deoxyadenosylcobalamin

Bioavailability: Intranasal:

Gel: 8.9% (relative to I.M.)

Solution: 6.1% (relative to I.M.)

Dosage:

Recommended daily allowance (RDA):

Children: 0.9-2.4 mcg/day

Adults: 2.4 mcg/day

Pregnancy: 2.6 mcg/day

Lactation: 2.8 mcg/day

Vitamin B12 deficiency:

Intranasal: 500 mcg in one nostril once weekly

Oral: 250 mcg/day

I.M., deep SubQ:

Children (dosage not well established): 0.2 mcg/kg for 2 days, followed by 1000 mcg/day for 2-7 days, followed by 100 mcg/week for one month; for malabsorptive causes of B12 deficiency, monthly maintenance doses of 100 mcg have been recommended or as an alternative 100 mcg/day for 10-15 days, then once or twice weekly for several months

Adults: Initial: 30 mcg/day for 5-10 days; maintenance: 100-200 mcg/month

Pernicious anemia: I.M., deep SubQ (administer concomitantly with folic acid if needed, 1 mg/day for 1 month):

Children: 30-50 mcg/day for 2 or more weeks (to a total dose of 1000-5000 mcg), then follow with 100 mcg/month as maintenance dosage

Adults: 100 mcg/day for 6-7 days; if improvement, administer same dose on alternate days for 7 doses, then every 3-4 days for 2-3 weeks; once hematologic values have returned to normal, maintenance dosage: 100 mcg/month. Note: Alternative dosing of 1000 mcg/day for 5 days (followed by 500-1000 mcg/month) has been used.

Hematologic remission (without evidence of nervous system involvement):

Intranasal gel: 500 mcg in one nostril once weekly

Oral: 1000-2000 mcg/day

I.M., SubQ: 100-1000 mcg/month

Schilling test: I.M.: 1000 mcg

Administration:

I.M./SubQ: I.M. or deep SubQ are preferred routes of administration

Intranasal: Nasal spray: Prior to initial dose, activate (prime) spray nozzle by pumping unit quickly and firmly until first appearance of spray, then prime twice more. The unit must be reprimed once immediately before each use.

I.V.: Not recommended due to rapid elimination

Oral: Not recommended due to variable absorption; however, oral therapy of 1000-2000 mcg/day has been effective for anemia if I.M./SubQ routes refused or not tolerated.

Monitoring Parameters:

Megaloblastic anemia: In addition to normal hematological parameters, serum potassium and platelet counts should be monitored during therapy

Reference Range:

Test Interactions:

Dietary Considerations:

Patient Education:

Nursing Implications:

Cardiovascular Considerations:

Schnyder, et al, studied the effects of homocysteine-lowering therapy (folic acid 1 mg/day, vitamin B6 10 mg/day, vitamin B12 0.4 mg/day) in patients with coronary artery disease after successful angioplasty in the Swiss Heart Study. This randomized, double-blind, placebo-controlled trial looked at a composite endpoint (death, nonfatal MI, repeat revascularization) 6 months and 1 year after angioplasty. Homocysteine-lowering therapy significantly decreased the incidence of major adverse events, primarily due to a reduced rate of target lesion revascularization. Investigators in the Folate After Coronary Intervention Trial randomized patients who underwent successful coronary stenting procedures to placebo or folic acid (1.2 mg/day), vitamin B6 (4.8 mg/day), and vitamin B12 (0.06 mg/day). Vitamin supplementation was associated with increased restenosis in these PCI patients.

Dental Health: Effects on Dental Treatment:

Dental Health: Vasoconstrictor/Local Anesthetic Precautions:

Mental Health: Effects on Mental Status:

Mental Health: Effects on Psychiatric Treatment:

Dosage Forms:

Gel, intranasal (Nascobal®): 500 mcg/0.1 mL (2.3 mL) [contains benzalkonium chloride; delivers 8 doses]

Injection, solution: 1000 mcg/mL (1 mL, 10 mL, 30 mL) [may contain benzyl alcohol and/or aluminum]

Lozenge [OTC]: 100 mcg, 250 mcg, 500 mcg

Solution, intranasal spray (Nascobal®): 500 mcg/0.1 mL actuation (2.3 mL) [contains benzalkonium chloride; delivers 8 doses]

Tablet [OTC]: 50 mcg, 100 mcg, 250 mcg, 500 mcg, 1000 mcg, 5000 mcg

Twelve Resin-K: 1000 mcg [may be used as oral, sublingual, or buccal]

Tablet, extended release [OTC]: 1500 mcg

Tablet, sublingual [OTC]: 2500 mcg

International Brand Names: