Cyanocobalamin - RxList

What Is Cyanocobalamin?

Cyanocobalamin (vitamin B12) is a man-made form of vitamin B12 used to treat low levels (deficiency) of Vitamin B12. A B12 deficiency may occur in certain health conditions (e.g., poor nutrition, stomach/intestinal problems, infection, cancer) and may result in anemia, stomach problems, and nerve damage. Cyanocobalamin is available in generic form.

What Are Side Effects of Cyanocobalamin?

Cyanocobalamin may cause serious side effects including:

• swelling,
• rapid weight gain,
• shortness of breath,
• pain when you breath,
• wheezing,
• gasping for breath,
• cough with foamy mucus,
• cold and clammy skin,
• anxiety,
• rapid heartbeats,
• leg cramps,
• constipation,
• irregular heartbeats,
• fluttering in your chest,
• increased thirst or urination,
• numbness or tinging, and
• muscle weakness or limp feeling

Get medical help right away, if you have any of the symptoms listed above.

Common side effects of Cyanocobalamin include:

• injection site reactions (pain, redness, swelling, irritation),
• diarrhea,
• nausea,
• upset stomach,
• itching,
• rash,
• headache,
• dizziness,
• weakness,
• numbness or tingling,
• fever,
• joint pain, or
• a feeling of swelling all over the body.

Cyanocobalamin may cause low potassium levels in the blood (hypokalemia). Tell your doctor if you have unlikely but serious side effects of Cyanocobalamin including:

• muscle cramps, or
• irregular heartbeat.

Seek medical care or call 911 at once if you have the following serious side effects:

• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Cyanocobalamin

To treat pernicious anemia a dose of 100 mcg daily of Cyanocobalamin for 6 or 7 days should be administered by intramuscular or deep subcutaneous injection.

What Drugs, Substances, or Supplements Interact with Cyanocobalamin?

Cyanocobalamin may interact with drugs that may affect blood cell production (e.g., chloramphenicol, anti-cancer drugs, HIV drugs), or supplements such as folic acid. Tell your doctor all medications and supplements you use.

Cyanocobalamin During Pregnancy and Breastfeeding

During pregnancy, Cyanocobalamin should be used only when prescribed. This medication may pass into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Cyanocobalamin (vitamin B12) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.