Pregnancy & Lactation: Risk data not available
What is Vitamin B-12?
Vitamin B12 is a vitamin that keeps your body’s blood and nerve cells healthy and also helps make DNA.
It’s sold as cyanocobalamin — a man-made form of the nutrient.
This medicine is given to treat or prevent a vitamin B12 deficiency in people with pernicious anemia or other medical conditions, both in an oral tablet and injectable form (to increase absorption).
Most people get enough vitamin B12 from the foods they eat, but according to the National Institutes of Health (NIH), between 1.5 percent and 15 percent of Americans have a vitamin B12 deficiency.
Warnings
What is the most important information I should know about Vitamin B-12 (Cyanocobalamin (Injection))?
You should not use this medicine if you are allergic to cobalt or if you have Leber's disease. Cyanocobalamin can lead to optic nerve damage (and possibly blindness) in people with Leber's disease.
Ask a doctor or pharmacist if this medicine is safe to use if you have ever had:
- low levels of calcium or potassium in your blood;
- heart disease;
- a stroke;
- a bleeding or blood clotting disorder such as hemophilia;
- diabetes;
- an iron or folic acid deficiency;
- kidney disease; or
- any condition that makes it hard for your body to absorb nutrients from food (malabsorption).
Ask a doctor before using this medicine if you are pregnant or breastfeeding.
Do not give this medicine to a child without medical advice.
How should I use Vitamin B-12
Use Vitamin B-12 (Cyanocobalamin (Injection)) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
Carefully follow instructions about whether to take your cyanocobalamin with or without food.
Your dose needs may change if you become pregnant, if you breastfeed, or if you eat a vegetarian diet. Tell your doctor about any changes in your diet or medical condition.
Swallow the extended-release tablet whole and do not crush, chew, or break it. Take with a full glass of water.
Do not swallow a lozenge or sublingual tablet whole. Allow it to dissolve in your mouth without chewing. Cyanocobalamin sublingual tablet or liquid should be placed under your tongue.
Pernicious anemia is also treated with folic acid to help maintain red blood cells. However, folic acid will not treat Vitamin B12 deficiency and will not prevent possible damage to the spinal cord. Take all of your medications as directed.
To treat pernicious anemia, you will have to use cyanocobalamin on a regular basis for the rest of your life. Not using the medication can lead to irreversible nerve damage in your spinal cord.
You may need frequent medical tests to help your doctor determine how long to treat you with cyanocobalamin. Using certain other medicines while taking cyanocobalamin may affect the results of these tests.
Store at room temperature away from moisture, heat, and light.
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
Vitamin B-12 side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
- easy bruising or bleeding (nosebleeds, bleeding gums);
- extreme tiredness;
- a light-headed feeling, like you might pass out;
- pale skin, blue lips or fingernails;
- eye pain, vision problems;
- headache, ringing in your ears;
- chest pain or tightness, fasts heartbeats;
- cough, wheezing, trouble breathing;
- trouble swallowing;
- little or no urination;
- heart problems--swelling, rapid weight gain, feeling short of breath;
- low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling; or
- signs of a blood clot in an arm or leg--pain, numbness, coldness, warmth, or pale appearance.
Common side effects may include:
- diarrhea; or
- rash.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect Vitamin B-12?
Avoid drinking large amounts of alcohol. Heavy drinking can make it harder for your body to absorb cyanocobalamin.
What to Expect
A vitamin B12 deficiency can cause symptoms such as tiredness, weakness, constipation, weight loss, loss of appetite, nerve problems, depression, confusion, balance problems, and more.
If you have a deficiency, you should start to feel better within a few days of taking a vitamin B12 supplement.
Additional Dosage Information
Your dosage will depend on your medical condition, your age, and other factors.
Some people with certain medical conditions, such as pernicious anemia, will have to take vitamin B12 for the rest of their lives. Pernicious anemia is an autoimmune condition that impairs the ability to absorb vitamin B12 through the digestive tract.
Secondary Uses
Your doctor may recommend vitamin B12 supplements for medical conditions that aren’t listed in this guide.