Vitamin B12

Uses of Cyanocobalamin Liquid:

• It is used to help with some kinds of anemia.
• It is used to treat or prevent low vitamin B12.
• It may be given to you for other reasons. Talk with the doctor.

What do I need to tell my doctor BEFORE I take Cyanocobalamin Liquid?

• If you have an allergy to cyanocobalamin or any other part of cyanocobalamin (B12) liquid.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you have an eye problem called Leber’s optic atrophy.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take cyanocobalamin (B12) liquid with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Cyanocobalamin Liquid?

• Tell all of your health care providers that you take cyanocobalamin (B12) liquid. This includes your doctors, nurses, pharmacists, and dentists.
• Have blood work checked as you have been told by the doctor. Talk with the doctor.
• Talk with your doctor before you drink alcohol.
• Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

How is this medicine (Cyanocobalamin Liquid) best taken?

Use cyanocobalamin (B12) liquid as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• To gain the most benefit, do not miss doses.
• Keep taking cyanocobalamin (B12) liquid as you have been told by your doctor or other health care provider, even if you feel well.
• It is best if cyanocobalamin (B12) liquid is taken with a meal.
• Shake well before use.
• Measure liquid doses carefully. Use the measuring device that comes with cyanocobalamin (B12) liquid. If there is none, ask the pharmacist for a device to measure cyanocobalamin (B12) liquid.

What do I do if I miss a dose?

• Take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of low potassium levels like muscle pain or weakness, muscle cramps, or a heartbeat that does not feel normal.
• Swelling, warmth, numbness, change of color, or pain in a leg or arm.
• Shortness of breath, a big weight gain, or swelling in the arms or legs.
• Change in balance.
• A burning, numbness, or tingling feeling that is not normal.
• Change in eyesight.

What are some other side effects of Cyanocobalamin Liquid?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Dizziness.
• Headache.
• Feeling tired or weak.
• Feeling nervous and excitable.
• Upset stomach or throwing up.
• Diarrhea.
• Signs of a common cold.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Cyanocobalamin Liquid?

• Store at room temperature. Do not freeze.
• Store in a dry place. Do not store in a bathroom.
• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

Consumer information use

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else’s drugs.
• Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
• Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
• Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about cyanocobalamin (B12) liquid, please talk with your doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

 

For the Consumer

Applies to cyanocobalamin: intramuscular solution

Other dosage forms:

• nasal spray

Along with its needed effects, cyanocobalamin may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking cyanocobalamin:

Incidence not known

• Abdominal or stomach pain
• bleeding from the gums or nose
• blue lips and fingernails
• chest pain
• cough
• coughing that sometimes produces a pink frothy sputum
• decreased urine output
• difficult, fast, noisy breathing, sometimes with wheezing
• difficulty with swallowing
• dilated neck veins
• dizziness
• extreme fatigue
• eye pain
• fast heartbeat
• headache
• hives, itching, or skin rash
• increased sweating
• irregular breathing
• irregular heartbeat
• pale skin
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• ringing in the ears
• swelling of the face, fingers, feet, or lower legs
• tightness in the chest
• unusual tiredness or weakness
• weight gain

Some side effects of cyanocobalamin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

• Diarrhea
• skin rash with a general disease

Usual Adult Dose for Pernicious Anemia

Initial dose: 1000 mcg intramuscularly or deep subcutaneous once a day for 6 to 7 days
If clinical improvement and reticulocyte response is seen from the above dosing:
-100 mcg every other day for 7 doses, then:
-100 mcg every 3 to 4 days for 2 to 3 weeks, then:
Maintenance dose: 100 to 1000 mcg monthly
Duration of therapy: Life

Comments:
-Administer concomitant folic acid if needed.
-Chronic treatment should be done with an oral preparation in patients with normal intestinal absorption.

Usual Adult Dose for B12 Nutritional Deficiency

25 to 2000 mcg orally daily

Usual Adult Dose for Schilling Test

1000 mcg intramuscularly is the flushing dose

Usual Pediatric Dose for B12 Nutritional Deficiency

0.5 to 3 mcg daily

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dialysis

Data not available

Other Comments

Administration advice:
-Avoid intravenous administration: almost all of the vitamin will be lost in the urine.
-Warm parenteral solution to body temperature before administration for patient comfort.

Monitoring:
-Pernicious anemia: monitor serum potassium closely during the first 48 hours of treatment and replace potassium if needed.

Patient advice:
-Patients with pernicious anemia will require B12 for the rest of their lives; failure to do so will cause anemia to return, which could lead to incapacitating and irreversible damage to the nerves and spinal cord.
-Taking folic acid instead of B12 may prevent anemia, but allow degeneration of the spinal cord.

Index Terms

• CaloMist
• Vitamin B₁₂

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Kit, Injection:

B-12 Compliance Injection: 1000 mcg/mL [contains benzyl alcohol]

Physicians EZ Use B-12: 1000 mcg/mL [contains benzyl alcohol]

Vitamin Deficiency System-B12: 1000 mcg/mL [contains benzyl alcohol]

Generic: 1000 mcg/mL [DSC]

Liquid, Sublingual:

Generic: 3000 mcg/mL (52 mL)

Lozenge, Oral:

Generic: 50 mcg (100 ea); 100 mcg (100 ea); 250 mcg (100 ea, 250 ea); 500 mcg (100 ea, 250 ea)

Solution, Injection:

Generic: 1000 mcg/mL (1 mL, 10 mL, 30 mL)

Solution, Nasal:

Nascobal: 500 mcg/0.1 mL (1 ea) [contains benzalkonium chloride]

Tablet, Oral:

Generic: 100 mcg, 250 mcg, 500 mcg, 1000 mcg

Tablet, Oral [preservative free]:

Generic: 100 mcg [DSC], 500 mcg [DSC], 1000 mcg

Tablet Extended Release, Oral:

Generic: 1000 mcg

Tablet Sublingual, Sublingual:

Generic: 2500 mcg [DSC]

Tablet Sublingual, Sublingual [preservative free]:

Generic: 2500 mcg

Brand Names: U.S.

• B-12 Compliance Injection
• Nascobal
• Physicians EZ Use B-12
• Vitamin Deficiency System-B12

Pharmacologic Category

• Vitamin, Water Soluble

Pharmacology

Coenzyme for various metabolic functions, including fat and carbohydrate metabolism and protein synthesis, used in cell replication and hematopoiesis

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

Metabolism

Converted in tissues to active coenzymes, methylcobalamin and deoxyadenosylcobalamin; undergoes some enterohepatic recycling

Excretion

Urine (50% to 98%, unchanged drug)

Onset of Action

Megaloblastic anemia: IM:

Conversion of megaloblastic to normoblastic erythroid hyperplasia within bone marrow: 8 hours

Increased reticulocytes: 2 to 5 days

Complicated vitamin B₁₂ deficiency: IM, SubQ: Resolution of:

Psychiatric sequelae: 24 hours

Thrombocytopenia: 10 days

Granulocytopenia: 2 weeks

Time to Peak

Serum: IM, SubQ: 30 minutes to 2 hours; Intranasal: 1.25 ± 1.9 hours

Protein Binding

Transcobalamins

Use: Labeled Indications

Vitamin B₁₂ deficiency: Treatment of pernicious anemia, vitamin B₁₂ deficiency due to dietary deficiencies, gastrointestinal malabsorption, folic acid deficiency, parasitic infestation, inadequate secretion of intrinsic factor, and inadequate utilization of B₁₂ (eg, during neoplastic treatment); treatment of increased B₁₂ requirements due to pregnancy, thyrotoxicosis, hemorrhage, malignancy, liver or kidney disease

Off Label Uses

Aphthous ulcers (recurrent)

Data from 2 small studies support the use of cyanocobalamin in reducing the frequency of recurrent aphthous ulcers in patients with normal or low serum vitamin B₁₂ levels at baseline ^{[Gulcan 2008]}, ^{[Volkov 2009]}.

Contraindications

Hypersensitivity to cyanocobalamin (vitamin B₁₂), cobalt, or any component of the formulation

Dosing: Adult

Aphthous ulcers, recurrent (off-label use):

Oral (sublingual): 1,000 mcg once every evening for 6 months (Volkov 2009)

IM: 1,000 mcg once daily for 7 days, followed by weekly for 1 month, followed by monthly for 6 months (Gulcan 2008)

Vitamin B₁₂ deficiency: Note: Folic acid supplementation may also be required.

Intranasal (Nascobal): 500 mcg in 1 nostril once weekly; may increase dose if vitamin B₁₂ levels decline after 1 month of treatment. Alternate route (eg, IM, SubQ) should be considered if B₁₂ levels are persistently low.

Oral: 1,000 to 2,000 mcg daily for 1 to 2 weeks; maintenance: 1,000 mcg daily (Langan 2011; Oh 2003)

IM, deep SubQ: May use initial treatment similar to that for pernicious anemia depending on severity of deficiency: 100 mcg daily for 6 to 7 days; if improvement, administer same dose on alternate days for 7 doses, then every 3 to 4 days for 2 to 3 weeks; once hematologic values have returned to normal, maintenance dosage: 100 mcg monthly.

Note: Higher doses may be preferred, especially in cases of severe deficiency; consider alternate dosing regimens with initial doses ranging from 100 to 1,000 mcg every day or every other day for 1 to 2 weeks and maintenance doses of 100 to 1,000 mcg every 1 to 3 months (Oh 2003) or 1,000 mcg once a week for 8 weeks followed by 1,000 mcg once a month (Langan 2011).

Mild B₁₂ deficiency (eg, malabsorption, atrophic gastritis, metformin use, chronic acid reducing medication use):

Oral: 500 to 1,000 mcg orally once daily (Stabler 2013)

IM: 1,000 mcg once daily or every other day for 1 week, then 1,000 mcg weekly for 4 to 8 weeks, and then 1,000 mcg monthly for life (Stabler 2013)

Pernicious anemia:

IM: 1,000 mcg once daily or every other day for 1 week, then 1,000 mcg weekly for 4 to 8 weeks, then 1,000 mcg once monthly for life (Stabler 2013) or 100 to 1,000 mcg every day or every other day for 1 to 2 weeks followed by 100 to 1,000 mcg every 1 to 3 months (Oh 2003) or 1,000 mcg once a week for 8 weeks followed by 1,000 mcg once a month for life (Langan 2011)

Oral: 1,000 to 2,000 mcg once daily for life (Stabler 2013)

IM, deep SubQ: Initial: 100 mcg once daily for 6 to 7 days; if improvement, administer same dose on alternate days for 7 doses, then every 3 to 4 days for 2 to 3 weeks; maintenance (once hematologic values have returned to normal): 100 mcg once monthly for life

Severe B₁₂ deficiency (due to gastrectomy, ileal resection, inflammatory bowel disease, sprue):

IM: 1,000 mcg once daily or every other day for 1 week, then 1,000 mcg weekly for 4 to 8 weeks, then 1,000 mcg once monthly for life (Stabler 2013)

Oral: 1,000 to 2,000 mcg once daily for life (Stabler 2013).

Vitamin B₁₂ repletion in gastric bypass surgery patients: IM or SubQ: 1,000 mcg once daily until normal B₁₂ levels are achieved and then resume supplementations dosage (ASBMS [Parrott 2017]) or 1,000 mcg IM once daily or every other day for 1 week, then 1,000 mcg IM weekly for 4 to 8 weeks, followed by supplementation dosing (Stabler 2013).

Vitamin B₁₂ supplementation in gastric bypass surgery patients:

IM or SubQ: 1,000 mcg once monthly (ASMBS [Parrott 2017]) or 1,000 mcg once monthly to 1,000 to 3,000 mcg once every 6 to 12 months (if oral or intranasal therapy are ineffective) (AACE/TOS/ACE [Mechanick 2013]) or 1,000 mcg IM once monthly for life (Stabler 2013).

Oral: 350 to 500 mcg (disintegrating tablet, sublingual, or liquid) once daily (ASMBS [Parrott 2017]) or ≥1,000 mcg once daily (AACE/TOS/ACE [Mechanick 2013]) or 1,000 to 2,000 mcg orally once daily for life (Stabler 2013)

Intranasal: 500 mcg in one nostril once weekly (ASMBS [Parrott 2017]; AACE/TOS/ACE [Mechanick 2013]).

Vitamin B₁₂ supplementation to reduce toxicity associated with pemetrexed: IM: 1,000 mcg every 9 weeks, beginning 1 to 3 weeks prior to pemetrexed treatment initiation; continue for 3 weeks after last pemetrexed dose; administer with oral folic acid supplementation (Scagliotti 2008; Vogelzang 2003); may administer cyanocobalamin on the same day as pemetrexed.

Vitamin B₁₂ supplementation to reduce toxicity associated with pralatrexate: IM: 1,000 mcg every 8 to 10 weeks; administer with oral folic acid supplementation (O’Connor 2011); begin cyanocobalamin within 10 weeks prior to pralatrexate treatment initiation. After the initial dose, may administer cyanocobalamin on the same day as pralatrexate.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Pernicious anemia: Note: Concurrent folic acid supplementation may also be needed.

Manufacturer’s labeling: Infants, Children, and Adolescents: IM, SubQ: 100 mcg once daily for 6 to 7 days; if improvement occurs, administer 100 mcg on alternate days for 7 doses, then every 3 to 4 days for 2 to 3 weeks; once hematologic values have returned to normal, maintenance dose: 100 mcg monthly

Alternate dosing: Limited data available: Infants, Children, and Adolescents: IM, SubQ: Initial: 1,000 mcg/day for 2 to 7 days based upon clinical response; followed by 100 mcg once weekly for 4 weeks and then maintenance dose: 100 mcg/month; for severe anemia, a lower initial dose of 0.2 mcg/kg/dose for 2 days followed by the above regimen has been recommended due to potential hypokalemia observed during initial treatment of adults with severe anemia (Orkin 2015; Rasmussen 2001; Stabler 2013); however, in more recent experience, while some adult patients may experience hypokalemia with initial treatment, this is unlikely to be clinically significant (Carmel 2008). For infants and young children, some experts have recommended doses as low as 50 to 100 mcg (Orkin 2015).

Vitamin B12 deficiency, severe: Limited data available; dosing regimens variable:

Dietary deficiency: Infants (breastfed with vitamin B12 deficient mothers): IM: 250 to 1,000 mcg once daily for 1 to 2 weeks, followed by weekly dosing until patient recovers (Stabler 2013); patients with neurologic symptoms have been treated with doses of 1,000 mcg (Guez 2012; Roumeliotis 2012)

Malabsorption: Infants, Children, and Adolescents: IM: 250 to 1,000 mcg daily or every other day for 1 week, then weekly for 4 to 8 weeks, and then monthly for life; younger children should receive monthly doses of 100 mcg (Bjørke-Monsen 2011; Kliegman 2016; Stabler 2013). For infants and young children, some experts have recommended doses as low as 50 to 100 mcg (Orkin 2015).

Administration

IM, SubQ: IM or deep SubQ are the preferred routes of administration. IV administration is not recommended.

Intranasal: Nasal spray (Nascobal): Administer 1 hour before or 1 hour after ingestion of hot foods/liquids.

Oral: Not generally recommended due to variable absorption; however, oral therapy in appropriate doses has been effective for anemia if IM/SubQ routes refused or not tolerated. Some tablets are available for sublingual administration.

Dietary Considerations

Strict vegetarian diets (eg, without eggs or dairy products) may result in vitamin B₁₂ deficiency.

Adequate intake (IOM 1998):

1 to 6 months: 0.4 mcg daily

7 to 12 months: 0.5 mcg daily

Recommended intake (IOM 1998):

1 to 3 years: 0.9 mcg daily

4 to 8 years: 1.2 mcg daily

9 to 13 years: 1.8 mcg daily

≥14 years: 2.4 mcg daily

Pregnancy: 2.6 mcg daily

Lactation: 2.8 mcg daily

Storage

Injection: Clear pink to red solutions are stable at room temperature. Protect from light.

Intranasal spray: Store at 15°C to 30°C (59°F to 86°F); do not freeze. Protect from light.

Drug Interactions

Chloramphenicol (Systemic): May diminish the therapeutic effect of Vitamin B12. Monitor therapy

Colchicine: May decrease the serum concentration of Cyanocobalamin. Monitor therapy

Test Interactions

Methotrexate, pyrimethamine, and most antibiotics invalidate folic acid and vitamin B₁₂ diagnostic blood assays

Adverse Reactions

>10%:

Central nervous system: Headache (IM: 20%; intranasal: 4%)

Infection: Infection (12% to 13%)

Neuromuscular & skeletal: Asthenia (IM: 16%; intranasal: 4%)

1% to 10%:

Central nervous system: Paresthesia (4%)

Gastrointestinal: Glossitis (nasal: 4%), nausea (4%)

Respiratory: Rhinitis (4% to 8%)

Frequency not defined:

Cardiovascular: Cardiac failure, thrombosis (peripheral)

Dermatologic: Pruritus, skin rash (transient)

Endocrine & metabolic: Hypokalemia

Gastrointestinal: Diarrhea

Hematologic & oncologic: Polycythemia vera, thrombocythemia

Hypersensitivity: Anaphylactic shock (IM/SubQ)

Respiratory: Pulmonary edema

Miscellaneous: Swelling

Warnings/Precautions

Concerns related to adverse effects:

• CNS effects: Vitamin B₁₂ deficiency for >3 months results in irreversible degenerative CNS lesions; neurologic manifestations will not be prevented with folic acid unless vitamin B₁₂ is also given. Spinal cord degeneration might also occur when folic acid used as a substitute for vitamin B₁₂ in anemia prevention.

• Hypokalemia: According to the manufacturer, treatment of severe vitamin B₁₂ megaloblastic anemia may result in severe hypokalemia, sometimes fatal, due to intracellular potassium shift upon anemia resolution; however, in more recent experience, while some patients may experience hypokalemia with initial treatment, this is unlikely to be clinically significant (Carmel 2008).

• Thrombocytosis: Treatment of severe vitamin B₁₂ megaloblastic anemia may result in thrombocytosis.

Disease-related concerns:

• Leber disease: Patients with Leber disease who received B12 treatment have suffered from severe rapid optic atrophy. Use of cyanocobalamin in these patients is not recommended.

• Megaloblastic anemia: Vitamin B₁₂ doses >10 mcg daily may produce a hematologic response in patients with folate deficient megaloblastic anemia and mask previously unrecognized folate deficiency; vitamin B₁₂ is not a substitute for folic acid.

• Pernicious anemia: Appropriate use: IM/SubQ routes are used to treat pernicious anemia; oral and intranasal administration are not indicated until hematologic remission and no signs of nervous system involvement.

• Polycythemia vera: Vitamin B₁₂ deficiency masks signs of polycythemia vera; vitamin B₁₂ administration may unmask this condition.

Dosage form specific issues:

• Aluminum: The parenteral product may contain aluminum; toxic aluminum concentrations may be seen with high doses, prolonged use, or renal dysfunction. Premature neonates are at higher risk due to immature renal function and aluminum intake from other parenteral sources. Parenteral aluminum exposure of >4 to 5 mcg/kg/day is associated with CNS and bone toxicity; tissue loading may occur at lower doses (Federal Register, 2002). See manufacturer’s labeling.

• Benzyl alcohol and derivatives: Some dosage forms may contain benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension and cardiovascular collapse (AAP [“Inactive” 1997]; CDC 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors 2001); avoid or use dosage forms containing benzyl alcohol with caution in neonates. See manufacturer’s labeling.

• Intranasal administration: The effectiveness of intranasal cyanocobalamin in patients with allergic rhinitis, nasal congestion, and upper respiratory tract infections has not been determined. Defer treatment until symptoms have subsided.

Other warnings/precautions:

• IV administration: Avoid intravenous route; anaphylactic shock has occurred.

• Test dose: Intradermal test dose of vitamin B₁₂ is recommended for any patient suspected of cyanocobalamin hypersensitivity prior to intranasal or injectable administration.

Monitoring Parameters

Vitamin B₁₂, hemoglobin, hematocrit, erythrocyte and reticulocyte count; folate and iron levels should be obtained prior to treatment; vitamin B₁₂ and peripheral blood counts should be monitored 1 month after beginning treatment (and vitamin B₁₂ 1 month after each dosage adjustment if using intranasal formulation), then every 3 to 6 months thereafter.

Evaluate serum methylmalonic acid and total homocysteine levels at baseline (prior to supplementation) in untreated patients to confirm vitamin B12 deficiency (and extent of deficiency); repeat to confirm adequate supplementation (Stabler 2013).

Megaloblastic/pernicious anemia: In addition to normal hematological parameters, serum potassium and platelet counts should be monitored during therapy. Note: Some patients may develop hypokalemia during initial treatment; however, this is unlikely to be clinically significant (Carmel 2008).

Bariatric surgery: Vitamin B₁₂ levels at baseline and once a year postoperatively then every 3 to 6 months if supplemented; every trimester in pregnant females (Mechanick 2013). In patients on chronic administration of medications known to increase risk of B₁₂ deficiency (eg, colchicine, metformin, neomycin, nitrous oxide, proton pump inhibitors, seizure medication), screen every 3 months for the initial postoperative year and then annually (Parrott 2017). Serum methylmalonic acid (MMA) is the recommended assay to evaluate vitamin B₁₂ levels for patients who are asymptomatic, symptomatic, have a history of B₁₂ deficiency, or preexisting neuropathy (Parrott 2017). Monitor for early signs/symptoms of B₁₂ deficiency, including pernicious anemia (pale skin/eyes, glossitis, fatigue, anorexia, diarrhea) or neuropathy (numbness, paresthesia in extremities, ataxia, decreased reflexes), lightheadedness or vertigo, dyspnea, tinnitus, palpitations, and /or increased HR; monitor for advanced signs/symptoms of B₁₂ deficiency, including angina, HF symptoms and/or mental status changes (Parrott 2017).

Pregnancy Considerations

Water soluble vitamins cross the placenta. Absorption of vitamin B₁₂ may increase during pregnancy. Vitamin B₁₂ requirements may be increased in pregnant women compared to nonpregnant women. Serum concentrations of vitamin B₁₂ are higher in the neonate at birth than the mother (IOM 1998).

Patient Education

What is this drug used for?

• It is used to help with some kinds of anemia.

• It is used to treat or prevent low vitamin B₁₂.

• It may be given to you for other reasons. Talk with the doctor.

Frequently reported side effects of this drug

• Dizziness

• Headache

• Loss of strength and energy

• Anxiety

• Common cold symptoms

• Runny nose

• Diarrhea

• Vomiting

• Nausea

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

• Low potassium like muscle pain or weakness, muscle cramps, or an abnormal heartbeat.

• DVT like edema, warmth, numbness, change in color, or pain in the extremities.

• Vision changes

• Shortness of breath

• Burning or numbness feeling

• Excessive weight gain

• Change in balance

• Swelling of arms or legs

• Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

A total of 15 drugs are known to interact with cyanocobalamin.

• 2 moderate drug interactions
• 13 minor drug interactions

Check for interactions

Type in a drug name to check for interactions with cyanocobalamin.

Medications known to interact with cyanocobalamin

• aminosalicylic acid
• arsenic trioxide
• chloramphenicol
• cimetidine
• dexlansoprazole
• esomeprazole
• famotidine
• lansoprazole
• nizatidine
• omeprazole
• pantoprazole
• potassium chloride
• rabeprazole
• ranitidine
• ranitidine bismuth citrate

Cyanocobalamin disease interactions

There are 4 disease interactions with cyanocobalamin which include:

• hypokalemia
• optic nerve
• malabsorption
• renal impairment

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Sources Cited

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L. Fontana, T. E. Meyer, S. Klein, J. O. Holloszy. Long-term low-calorie low-protein vegan diet and endurance exercise are associated with low cardiometabolic risk. Rejuvenation Res 2007 10(2):225 – 234

S.-Y. Yang, X.-J. Li, W. Zhang, C.-Q. Liu, H.-J. Zhang, J.-R. Lin, B. Yan, Y.-X. Yu, X.-L. Shi, C.-D. Li, W.-H. Li. Chinese lacto-vegetarian diet exerts favorable effects on metabolic parameters, intima-media thickness, and cardiovascular risks in healthy men. Nutr Clin Pract. 2012 27(3):392 – 398.

T.-C. Su, P.-L. Torng, J.-S. Jeng, M.-F. Chen, C.-S. Liau. Arterial function of carotid and brachial arteries in postmenopausal vegetarians. Vasc Health Risk Manag. 2011 7:517 – 523.

 T.-C. Su, J.-S. Jeng, Jung-Der Wang, P.-L. Torng, S.-J. Chang, C.-F. Chen, C.-S. Liau. Homocysteine, circulating vascular cell adhesion molecule and carotid atherosclerosis in postmenopausal vegetarian women and omnivores. Atherosclerosis 2006 184(2):356 – 362.

A. D. Smith, H. Refsum. Do we need to reconsider the desirable blood level of vitamin B12? J. Intern. Med. 2012 271(2):179 – 182.

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