Medication

Crystal B-12

Generic name:

Pharmacist-reviewed drug information from the RxWiki encyclopedia.

Overview

Cyanocobalamin is a prescription medication used to used to treat and prevent a lack of vitamin B12.

Cyanocobalamin belongs to a group of drugs called vitamins. These help to supply vitamin B12.

This medication is available in an injectable form to be given directly into the muscle (IM) or under the skin by a healthcare professional.

Common side effects of cyanocobalamin include diarrhea and feeling as if your entire body is swollen.

What is it used for?

Cyanocobalamin is a prescription medication used to treat and prevent a lack of vitamin B12 that may be caused by any of the following:

  • pernicious anemia (lack of a natural substance needed to absorb vitamin B12 from the intestine)
  • folic acid deficiency
  • certain diseases
  • infections
  • malignancy of pancreas or bowel
  • medications that decrease the amount of vitamin B12 absorbed from food
  • a vegan diet (strict vegetarian diet that does not allow any animal products, including dairy products and eggs)

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

How to take it

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dose your doctor recommends may be based on the following:

  • the condition being treated
  • other medical conditions you have
  • other medications you are taking
  • how you respond to this medication

The recommended dose of cyanocobalamin for the treatment of pernicious anemia is 100 mcg a day. A dose of 100 mcg daily for 6 or 7 days should be administered. If there is clinical improvement the same amount may be given on alternate days for seven doses, then every 3 to 4 days for another 2 to 3 weeks. The regimen will depend on you respond to cyanocobalamin.

This regimen should be followed by 100 mcg monthly for life.

Warnings

Serious side effects have been reported with cyanocobalamin including the following:

  • Hypokalemia and sudden death may occur in severe megaloblastic anemia.
  • Anaphylactic shock and death. Anaphylactic shock and death have been reported after cyanocobalamin administration.
  • "Gasping Syndrome" in premature infants. This product contains Benzyl Alcohol. Benzyl Alcohol has been reported to be associated with a fatal "Gasping Syndrome" in premature infants.
  • Aluminum toxicity. This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged administration in patients with impaired kidney function.
  • Congestive heart failure. Tell your healthcare provider right away if you experience any of the following symptoms of CHF:
    • sudden weight gain
    • worsening shortness of breath
    • increased swelling of your feet, legs, or abdomen
    • needing to use more pillows to go to sleep or sleeping in a recliner
    • waking from sleep to catch your breath
    • a cough that does not go away
    • new or increasing irregularities in your heart rate
  • Production of too many red blood cells.

Do not take cyanocobalamin if you:

  • are allergic to cyanocobalamin or to any of its ingredients
  • have sensitivity to cobalt

Side effects

Serious side effects have been reported with cyanocobalamin. See the “Cyanocobalamin Precautions” section.

Common side effects of cyanocobalamin include the following:

  • diarrhea
  • feeling as if your entire body is swollen
  • itching
  • eruption of the skin
  • diarrhea

This is not a complete list of cyanocobalamin side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Drug interactions

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • antibiotics such as chloramphenicol (Chloromycetin, Mychel-S)
  • colchicine (Colcrys)
  • folic acid
  • methotrexate (Rheumatrex, Trexall)
  • para-aminosalicylic acid (Paser)
  • pyrimethamine (Daraprim)

Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

This is not a complete list of cyanocobalamin drug interactions. Ask your doctor or pharmacist for more information.

Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Cyanocobalamin falls into category C.There are no well-controlled studies that have been done in pregnant women. Cyanocobalamin should be used during pregnancy only if the possible benefit outweighs the possible risk to the unborn baby.

However, vitamin B12 is an essential vitamin and requirements are increased during pregnancy. Amounts of vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for pregnant women (4 mcg daily) should be consumed during pregnancy.

Breastfeeding

Tell your doctor if you are breastfeeding or plan to breastfeed.

Cyanocobalamin has been detected in human breast milk.

Amounts of vitamin B12 that are recommended by the Food and Nutrition Board, National Academy of Science-National Research Council for lactating women (4 mcg daily) should be consumed during lactation.

Quick facts

Unless your doctor tells you otherwise, continue your normal diet.

The need for vitamin B12 is increased by pregnancy and lactation.

In some cases, folic acid may need to be administered while taking cyanocobalamin.

All information on this site is provided “as-is” for informational purposes only and is not a substitute for medical advice or treatment. You should consult with a medical professional if you have any questions about your health.