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What is oral cyanocobalamin?
Cyanocobalamin is a man-made form of vitamin B12. Vitamin B12 is important for growth, cell reproduction, blood formation, and protein and tissue synthesis. Cyanocobalamin is used to treat vitamin B12 deficiency in people with pernicious anemia and other conditions. Cyanocobalamin may also be used for purposes other than those listed in this medication guide.

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What are the possible side effects of oral cyanocobalamin?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

• chest pain;

• feeling short of breath, even with mild exertion;

• swelling, rapid weight gain; or

• unusual warmth, redness, or pain in an arm or leg.

Less serious side effects may include:

• headache, dizziness, weakness;

• nausea, upset stomach, diarrhea;

• numbness or tingling;

• fever;

• joint pain;

• swollen tongue;

• swelling; or

• itching or rash.

This list is not complete and other side effects may occur. Tell your doctor about any unusual or bothersome side effect.

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How should I take oral cyanocobalamin?
Use this medication exactly as prescribed by your doctor. Do not use it in larger amounts or for longer than recommended. Follow the directions on your prescription label. Your dose needs may change if you become pregnant, if you breast-feed, or if you eat a vegetarian diet. Tell your doctor about any changes in your diet or medical condition. Take oral cyanocobalamin with a full glass of water. The sublingual tablet should be placed under your tongue where it will dissolve. Do not crush, chew, break an extended-release tablet. Swallow the pill whole. Breaking or opening the pill may cause too much of the drug to be released at one time.

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What is the most important information I should know about oral cyanocobalamin?
You should not use this medication 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. To treat pernicious anemia, you will have to use this medication on a regular basis for the rest of your life. Not using the medication can lead to irreversible nerve damage in your spinal cord. 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.

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What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.

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What other drugs will affect oral cyanocobalamin?
Before taking cyanocobalamin, tell your doctor if you are taking any of the following medications: antibiotics; methotrexate (Rheumatrex); pyrimethamine (Daraprim); colchicine; or if you drank a lot of alcohol within the past 2 weeks. This list is not complete and there may be other drugs that can interact with cyanocobalamin. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Cyanocobalamin has been assigned to pregnancy category C by the FDA. Studies have revealed a progressive decline in the maternal serum level and an increase in the urinary excretion of vitamin B12 during pregnancy. The fetus has been shown to concentrate vitamin B12 since fetal cord serum levels are approximately three times maternal values. In view of a demonstrated increase in urinary excretion of vitamin B12 during pregnancy, the recommended daily allowance (RDA) during pregnancy includes the addition of 1 mcg/day above the basal requirement of 3 mcg/day.

Cyanocobalamin is excreted into human milk. Cyanocobalamin is considered compatible with breast-feeding by the American Academy of Pediatrics

In animals, vitamin B12 deficiency is associated with teratogenic effects. Methylmalonic aciduria, homocystinuria, megaloblastic anemia and neurologic abnormalities have been reported in breast-fed infants whose mothers were strict vegetarians. In general, severe maternal vitamin B12 deficiency may result in megaloblastic anemia with subsequent infertility and poor pregnancy outcomes. Milk concentrations are proportional to the daily intake of the vitamin. Women given daily doses of 1 to 200 micrograms/day had milk levels increase from a level of 79 pg/mL to 100 pg/mL. In a study using 8 micrograms/day of cyanocobalamin, mean milk levels of 1650 pg.mL at 1 week and 1100 pg/mL at 6 weeks were measured. Corresponding levels in unsupplemented mothers were 1220 and 610 pg./mL, respectively.

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Who should NOT use this medication?

• Known hypersensitivity to vitamin B₁₂, cobalt, or any ingredient in the formulation.
• No contraindications when used for treatment of cyanide poisoning.

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What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine. An overdose of cyanocobalamin is not likely to cause life-threatening symptoms.

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What should I discuss with my healthcare provider before taking oral cyanocobalamin?
You should not use this medication 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. Before using cyanocobalamin, tell your doctor if you have: any type of infection; iron or folic acid deficiency; kidney or liver disease; or if you are receiving any medication or treatment that affects bone marrow. If you have any of these conditions, you may need a dose adjustment or special tests to safely take oral cyanocobalamin.

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Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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Where can I get more information?
More Information

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