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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Limited Use [what does this mean?]
Generic drug name: vitamin B12 [cyanocobalamin] (sye an oh koe BAL a min)
Brand name(s):
GENERIC: available FAMILY: Vitamins
Find the drug label by searching at DailyMed.

Limited Use [what does this mean?]
Generic drug name: vitamin B12 injection
Brand name(s):
GENERIC: available FAMILY: Vitamins
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

Vitamins taken at the level that supplies normal body needs (not megadoses) do not pose a risk to the fetus.

Breast-feeding Warning

Vitamin B12 is excreted into breast milk. No problems have been found in nursing infants of women taking the normal daily recommended amounts.

Facts About This Drug [top]

 

FOODS HIGH IN VITAMIN B12
Tongue, beef, pork, organ meats, eggs, nuts, milk, shellfish, poultry, cheese (all may be high in cholesterol and/or fat), fish, peas, beans, lentils, tofu.  Cooking is not likely to destroy vitamin B12.
1 ounce beef liver 9.0–34.0 micrograms vitamin B12
3½ ounces round roast 4.0 micrograms vitamin B12
3½ ounces filet of sole 1.3 micrograms vitamin B12
1 ounce Swiss...

 

FOODS HIGH IN VITAMIN B12
Tongue, beef, pork, organ meats, eggs, nuts, milk, shellfish, poultry, cheese (all may be high in cholesterol and/or fat), fish, peas, beans, lentils, tofu.  Cooking is not likely to destroy vitamin B12.
1 ounce beef liver 9.0–34.0 micrograms vitamin B12
3½ ounces round roast 4.0 micrograms vitamin B12
3½ ounces filet of sole 1.3 micrograms vitamin B12
1 ounce Swiss cheese 9.0 micrograms vitamin B12

Vitamin B12, also called cyanocobalamin, is essential for cell growth and normal formation of blood cells. It is found in several kinds of foods (see box above), and a well-balanced diet with a variety of healthful foods should supply all the vitamin that your body needs. The recommended dietary allowance (RDA) of vitamin B12 for older adults is 2.4 micrograms per day.

Even if you do not get enough vitamin B12 in your diet, a vitamin B12 deficiency may take years to develop because the liver stores a vast supply of this vitamin. You may develop a deficiency from certain physical conditions or from an inadequate diet. In adults, a vitamin B12 deficiency usually comes from a defect in the digestive tract’s absorption of the vitamin, a condition called pernicious anemia. You may also develop a deficiency if you have had parts of your stomach or small intestine removed, which prevents the digestive tract from adequately absorbing the vitamin. In both of these cases, you need vitamin B12 injections. Since plants do not contain vitamin B12, strict vegetarians who do not eat eggs or milk products also need a vitamin B12 supplement and can take one by mouth.

Vitamin B12 deficiency can lead to anemia and to slow, progressive, irreversible damage to the nervous system. This damage will cause loss of feeling in the hands and feet, unsteadiness, loss of memory, confusion, and moodiness. To prevent these changes, people who require lifelong treatment with monthly B12 injections should be reevaluated at 6- to 12-month intervals by their doctor if they are otherwise well.[1]

Unless you have one of the conditions that require B12 injections, to prevent and treat a deficiency of vitamin B12 you should eat more food that is rich in this vitamin rather than taking a vitamin supplement. You should take a supplement only if your diet does not provide an adequate amount.

The claims made for vitamin B12 as a remedy for numerous conditions are unfounded. There is no evidence that supplements can provide more pep or counter depression or fatigue in people who do not have a deficiency.

A recent Journal of Parenteral and Enteral Nutrition (JPEN) systematic review revealed that, with a few possible exceptions, dietary supplements offer no benefits to well-nourished adults eating a Western diet and, in many cases, may be harmful. The results of this study reinforce Worst Pills, Best Pills News’ longstanding view that there is little evidence that dietary supplements are either safe or effective.

The study authors concluded that with the possible exception of vitamin D in elderly patients and omega-3 fatty acids in patients with a history of cardiovascular disease, no data support the widespread use of dietary supplements in the U.S. and other Western countries. Indeed, the data suggest that certain commonly used dietary supplements, including beta-carotene, vitamin A and vitamin E, may be harmful. We agree.[2]

Before You Use This Drug [top]

Do not use if you have or have had:

  • Leber’s disease (an eye disease)

Tell your doctor if you have or have had:

  • allergy to cyanocobalamin or hydroxocobalamin
  • pregnancy or are breast-feeding

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

How to Use This Drug [top]

  • Take at least one hour before or one hour after hot foods or liquids.
  • Have follow-up blood tests every three to six months.
  • If you miss a dose, take it as soon as you remember, but skip it if it is almost time for the next dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

8Evaluations of Drug Interactions 2003 lists no drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods as causing “highly clinically significant” or “clinically significant” interactions when used together with the drugs in this section. We also found no interactions in the drugs’ FDA-approved professional package inserts. However, as the number of new drugs approved for marketing increases and as more experience is gained with these drugs over time, new interactions may be discovered.

Adverse Effects [top]

Call your doctor if these symptoms continue:

  • diarrhea
  • skin itching

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • blood levels of folic acid
  • potassium blood tests
  • vitamin B12 blood tests
  • iron and clotting blood tests
  • reticulocyte (young red blood cell) count

last reviewed May 31, 2021