Cyanocobalamin Side Effects

Brand Names: Nascobal

Please note - some side effects for Cyanocobalamin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Cyanocobalamin - for the Consumer

Cyanocobalamin (B12)

All medicines may cause side effects, but many people have no, or minor, side effects. If any of the following most COMMON side effects continue or become bothersome when using Cyanocobalamin (B12), check with your doctor: Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cyanocobalamin (B12):

Mild, temporary diarrhea.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); calf pain, swelling, or tenderness; chest pain; feeling of swelling throughout the entire body; fever, chills, or persistent sore throat; irregular heartbeat; muscle weakness or cramping; shortness of breath; unusual bruising or bleeding.

Cyanocobalamin/Vitamin C/Folic Acid/Iron

All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cyanocobalamin/Vitamin C/Folic Acid/Iron:

Constipation; dark or green stools; diarrhea; nausea; stomach pain; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry, or bloody stools; severe or persistent stomach pain.

Cyanocobalamin/Vitamin C/Folic Acid/Iron/Succinic Acid

All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cyanocobalamin/Vitamin C/Folic Acid/Iron/Succinic Acid:

Constipation; dark or green stools; diarrhea; nausea; stomach pain; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry, or bloody stools; severe or persistent stomach pain.

Cyanocobalamin/Folic Acid/Iron/Vitamin C

All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cyanocobalamin/Folic Acid/Iron/Vitamin C:

Constipation; dark or green stools; diarrhea; nausea; stomach pain; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry, or bloody stools; severe or persistent stomach pain.

Cyanocobalamin (B12) Chewable Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. When used in small doses, no COMMON side effects have been reported with Cyanocobalamin (B12) Chewable Tablets. Seek medical attention right away if any of these SEVERE side effects occur when using Cyanocobalamin (B12) Chewable Tablets:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue).

Cyanocobalamin (B12) Controlled-Release Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. When used in small doses, no COMMON side effects have been reported with Cyanocobalamin (B12) Controlled-Release Tablets. Seek medical attention right away if any of these SEVERE side effects occur when using Cyanocobalamin (B12) Controlled-Release Tablets:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue).

Cyanocobalamin (B12) Spray

All medicines may cause side effects, but many people have no, or minor, side effects. When used in small doses, no COMMON side effects have been reported with Cyanocobalamin (B12) Spray. Seek medical attention right away if any of these SEVERE side effects occur when using Cyanocobalamin (B12) Spray:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); calf swelling or tenderness; chest pain; irregular heartbeat; muscle weakness or cramping; shortness of breath; swelling of the hands, ankles, or feet; unusual bruising.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch .

Cyanocobalamin (B12) Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. When used in small doses, no COMMON side effects have been reported with Cyanocobalamin (B12) Tablets. Seek medical attention right away if any of these SEVERE side effects occur when using Cyanocobalamin (B12) Tablets:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue).

Cyanocobalamin Side Effects - for the Professional

Cyanocobalamin

Generalized: Anaphylactic shock and death have been reported with administration of parenteral vitamin B12.

Cardiovascular: Pulmonary edema and congestive heart failure early in treatment; peripheral vascular thrombosis.

Hematological: Polycythemia vera

Gastrointestinal: Mild transient diarrhea

Dermatological: Itching; transitory exanthema

Miscellaneous: Feeling of swelling of entire body

Side Effects by Body System

Cardiovascular

Cardiovascular side effects associated with parenteral cyanocobalamin have included congestive heart failure, pulmonary edema, and peripheral vascular thrombosis. These effects were usually reported early in treatment.

Dermatologic

Dermatologic side effects associated with both intranasal and parenteral cyanocobalamin have included itching and transitory exanthema.

Dermatologic side effects have rarely included exacerbation or onset of inflammatory acne and folliculitis related to B12.

Exacerbation or onset of inflammatory acne and folliculitis have been seen with high doses of B12 (5 to 10 mg/week). The etiology and pathogenic mechanisms of vitamin B12-induced acne are unknown. When present, acneiform eruptions usually occur on the facial area after the first or second injection, and typically disappear within 8 to 10 days after stopping therapy.

A single case of a severe skin eruption resembling acne rosacea that was temporally associated with daily ingestion of 100 mcg of B12 (with 100 mg of B6) has been reported. The rash resolved upon discontinuation of both drugs and recurred upon rechallenge with half the doses.

Some have suspected sorbitol or iodine that is present in some ampules of B12 may be the cause of at least some cases of skin eruptions associated with this drug.

Gastrointestinal

A single case of cecal vitamin B12 bezoar has been reported in an elderly man with a history of multiple gastrointestinal surgeries.

Gastrointestinal side effects associated with parenteral cyanocobalamin have included dyspepsia, nausea, vomiting, and mild transient diarrhea.

Gastrointestinal side effects associated with intranasal cyanocobalamin have included glossitis and nausea.

Hypersensitivity

Anaphylactic reactions have been reported primarily with parenteral administration of B12 and are thought to be the result of impurities of B12 preparations that are no longer manufactured. They may occur soon after a sensitizing dose, within a few weeks or months, or rarely after a latency of several years.

Hypersensitivity side effects associated with parenteral cyanocobalamin have rarely included anaphylactic reactions and death.

Nervous system

Nervous system side effects associated with parenteral cyanocobalamin have included abnormal gait, asthenia, anxiety, dizziness, hypoesthesia, incoordination, nervousness, and incoordination.

Nervous system side effects associated with both parenteral and intranasal cyanocobalamin have included paresthesia and headache.

Hematologic

Hematologic side effects have included polycythemia vera.

Musculoskeletal

Musculoskeletal side effects associated with parenteral cyanocobalamin have included arthritis, back pain, and myalgia.

Respiratory

Respiratory side effects associated with parenteral cyanocobalamin have included dyspnea.

Respiratory side effects associated with both parenteral and intranasal cyanocobalamin have included rhinitis.

Immunologic

Immunologic side effects associated with both parenteral and intranasal cyanocobalamin have included infection.

Other

Other side effects associated with parenteral administration of cyanocobalamin have included feeling of swelling of entire body, back pain, and generalized pain.

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