Vitamin B12 injections are typically prescribed to treat deficiencies of vitamin B12 caused by malabsorption conditions, a macrobiotics (grains, vegetables and beans) diet or a strict vegetarian diet. Vitamin B12 shots are administered through a deep intramuscular injection by a health care professional when sufficient B12 cannot be achieved through food or oral or nasal B12 supplements. The dosage varies according to the deficiency, but typically progresses from daily, weekly, monthly and less-frequent regime.
Significance
Vitamin B12 injections may be required in people with a medical condition called pernicious anemia, which occurs when vitamin B12 is not absorbed from the intestine. People that have had a portion of their intestine removed, part of their stomach eliminated or have a diseased intestine, may also need B12 injections. People who follow a macrobiotic diet may also require B12 supplements in the form of injections. Since vegetables do not contain vitamin B12 according to MayoClinic.com, strict vegetarians may need B12 injections.
Precaution
A vitamin B12 deficiency may lead to nerve damage, anemia and stomach problems, reports MayoClinic.com. Anemia can lead to you feeling tired and short of breath. You may also be more prone to infections if you are anemic. Nerve degeneration and neurological damage may occur with a long-term vitamin B12 deficiency.
The Facts
Adolescents, females and males age 14 and over require 2.4 mcg of vitamin B12 daily, according to the National Institute of Health Office of Dietary Supplements. Adolescent and adult pregnant females require 2.6 mcg daily. Adolescent and adult pregnant females who are breastfeeding require 2.8 mcg daily. The recommended dosage for children varies by age in the range of 0.4 mcg and 1.8 mcg daily. Those over 50 years of age, who do not meet the recommended daily allowance should take a B12 supplement or eat foods fortified with B12. Older people may need to take a 25- to 100-mcg B12 supplement daily to maintain the recommended B12 levels, reports MayoClinic.com.
Frequency
To treat a vitamin B12 deficiency caused by pernicious anemia or other malabsorption condition, the frequency of your B12 injection will vary depending on your B12 levels. Typically, 1,000 μg is given daily for five days, and then 1,000 mg is given weekly for four weeks, reports Oregon Health and Science University. Your physician may require maintenance injections of 1,000 μg between one and three months.
Side Effects
Vitamin B12 injections do not typically cause side effects other than soreness at the injection site. Contact your health care professional is skin rash, itching, wheezing, diarrhea, hives, difficulty breathing, facial or lip swelling, chest pain, shortness of breath, redness, warmth or pain in the legs, headache, dizziness, weakness, numbness, nausea, fever, or joint pain, reports Drugs.com.
Warning
Those who suffer from or have a family history of Leber's Disease, a hereditary optic nerve atrophy, or who are allergic to cobalt, should not take vitamin B12 injections.
References
- National Institute of Health Office of Dietary Supplements: Dietary Supplement Fact Sheet: Vitamin B12
- MayoClinic.com: Vitamin B12 - Dosing
- MayoClinic.com: Vitamin B12 - Nasal Route, Oral Route, Parenteral Route
- Oregon Health and Science University: Cyanocobalamin: Vitamin B12
- Drugs.com: Vitamin B12
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