Vitamin B12, a water-soluble vitamin, plays an important role in red blood cell production, growth and development and neurological function. Most people get enough vitamin B12 from dietary sources, including meat and fish. People who do not eat animal products or who cannot absorb vitamin B12 from food may need supplements in oral, nasal or injectable form to prevent or treat vitamin B12 deficiency. Vitamin B12 has few side effects and overdose does not occur even when patients receive high doses.
Injectable Vitamin B12
Injectable cyanocobalamin, a synthetic form of vitamin B12, comes in sterile vials. Most patients receive injections at the health care provider's office, but some administer them to themselves at home according to a doctor's instructions and prescription. The dose varies according to the patient's underlying condition. To treat pernicious anemia, a serious form of anemia that occurs in people who cannot absorb B12 from food, you may need to take injections every day for two weeks, then at longer intervals until your blood levels become normal. Most patients take monthly maintenance doses for the rest of their lives.
Vitamin B12 Overdose
The Institute of Medicine, a nonprofit organization that provides information on nutrients and other scientific information to the federal government, has determined that vitamin B12 has a low potential for toxicity, according to the U.S. Office of Dietary Supplements. In fact, healthy individuals do not experience adverse effects from excessive vitamin B12 intake from food or supplements because their bodies excrete the excess.
Considerations
Some individuals may have higher than normal B12 blood levels due to liver disease or leukemia, but these conditions are rare, according to MedLinePlus. If you have Leber's disease, a hereditary eye condition, taking vitamin B12 in any form could cause damage to your optic nerve, including blindness, according to Drugs.com. The same effect may occur if you have an allergy to cobalt and take vitamin B12. Tell your health care provider if you have an infection, iron or folate deficiency, liver disease, kidney disease or are undergoing treatment that affects the bone marrow, as these conditions may require an adjustment in your B12 dosage. The effects of B12 on a fetus or nursing infant are unknown, so tell your health care provider if you are pregnant or breastfeeding.
Side Effects
Side effects of B12 injections may include shortness of breath, diarrhea, feeling swollen, weakness, cramps, leg pain, wheezing, coughing, urinary frequency, thirst, confusion, rapid heart rate, tenderness in one leg, dizziness, headache, hives, rash, itching, difficulty swallowing or reddened skin, according to MedLinePlus. Contact your health care provider or seek emergency medical treatment if your symptoms become severe and persistent.
Member Comments