Vitamin B12

What is it?
Vitamin B12 is a vitamin used to treat Vitamin B12 deficiency (low Vitamin B12), sleeping problems, and impaired mental functioning of the elderly. It may also be used to treat a low sperm count, tinnitus (ringing in ears), AIDS, asthma, and multiple sclerosis.

Other names for Vitamin B12 include: Bedumil, Cobamin, Cyanocobalaminum, Methylcobalamin, and Cycobemin.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:
Tell your doctor if you

• are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
• are pregnant or plan to become pregnant while using this medicine
• are breastfeeding
• have Leber's disease (inherited eye problems)
• have any other health problems, such as high blood pressure or heart or blood vessel disease

Dosage:
Talk with your caregiver about how much Vitamin B12 you should take. The amount depends on the strength of the medicine and the reason you are taking Vitamin B12. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:
Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.

Drug and Food Interactions:
Do not take Vitamin B12 without talking to your doctor first if you are taking:

• Aminosalicylic Acid
• Ascorbic Acid (Vitamin C)
• Chloramphenicol
• Omeprazole (Prilosec(R))

Warnings:

• Before taking Vitamin B12, tell your doctor if you are pregnant or breastfeeding
• Strict vegetarians may have symptoms of Vitamin B12 deficiency (1)
• The older adult may have Vitamin B12 deficiency caused by lower intestinal (colon) absorption (trouble getting it into the body) (1)
• Do not use if you have Leber's disease (eye problems) (5)
• Some medicines may make your body need more Vitamin B12 (examples: Cimetidine (Tagamet(R)), Birth Control Pills, Ranitidine (Zantac(R)). Talk to your doctor about the need to take Vitamin B12 supplements (8,10)

Side Effects:
Stop taking your medicine right away and talk to your doctor if you have any of the following side effects. Your medicine may be causing these symptoms which may mean you are allergic to it.

• Breathing problems or tightness in your throat or chest
• Chest pain
• Skin hives, rash, or itchy or swollen skin

Other Side Effects:
You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.

• Diarrhea (loose stools) (3)

References:
1. National Research Council: Vitamin B12. Recommended Dietary Allowances, 10th ed. National Academy Press, Washington, DC; 1998.
2. Anon: Drug Facts and Comparisons. Facts and Comparisons Inc, St Louis, MO; 1998.
3. USPDI: Drug Information for the Health Care Professional, 13th ed. US Pharmaceutical Convention Inc, Rockville, MD; 1993.
4. AMA Department of Drugs: AMA drug evaluations subscription. American Medical Association, Chicago, IL; 1991.
5. Foulds WS, Freeman AG, Phillips CI et al: Cyanocobalamin: a case for withdrawal (letter). Lancet 1970; 1(7636): 35.
6. Marcus M, Prabhudesai M & Wassef S: Stability of vitamin B12 in the presence of ascorbic acid in food and serum: restoration by cyanide of apparent loss. Am J Clin Nutr 1980; 33(1): 137-143.
7. Jiji RM, Gangarosa EJ & de la Macorra F: Chloramphenicol and its sulfamoyl analogue: report of reversable erythropoietic toxicity in healthy volunteers. Arch Intern Med 1963; 111: 70.
8. Salom IL, Silvis SE & Doscherholmen A: Effect of cimetidine on the absorption of vitamin B12. Scand J Gastroenterol 1982; 17(1): 129-131.
9. Marcuard SP, Albernaz L & Khazanie PG: Omeprazole therapy causes malabsorption of cyanocobalamin (vitamin B12). Ann Intern Med 1994; 120(3): 211-215.
10. Hjelt K, Brynskov J, Hippe E et al: Oral contraceptives and the cobalamin (vitamin B12) metabolism. Acta Obstet Gynecol Scan 1985; 64(1): 59-63.