See also Precautions section.

Cyanocobalamin is a man-made form of vitamin B12 used to prevent and treat low blood levels of this vitamin. Most people get enough vitamin B12 from their diet. Vitamin B12 is important to maintain the health of your metabolism, blood cells, and nerves. Serious vitamin B12 deficiency may result in a low number of red blood cells (anemia), stomach/intestine problems, and permanent nerve damage.

Vitamin B12 deficiency may occur in certain health conditions (such as intestinal/stomach problems, poor nutrition, cancer, HIV infection, pregnancy, old age, alcoholism). It may also occur in people who follow a strict vegetarian (vegan) diet.

If you are taking the over-the-counter product to self-treat, follow all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has directed you to take this medication, take as directed by your doctor.

Take this medication by mouth with or without food as directed by your doctor or the product package, usually once daily. Use this product regularly to get the most benefit from it. To help you remember, take it at the same time each day.

The dosage is based on your medical condition, response to treatment, and lab tests. Consult your doctor or pharmacist for more details.

There are many brands and forms of cyanocobalamin (vitamin B12) available. Read the dosing instructions carefully for each product because the amount of cyanocobalamin (vitamin B12) may be different between products.

If you are using the liquid form of this medication, carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. Some liquid brands may require you to shake the bottle well before each dose.

If you are taking the extended-release tablets, do not crush or chew them. Doing so can release all of the drug at once, increasing the risk of side effects. Swallow the tablets whole.

If you are taking the chewable tablet, chew the medication thoroughly before swallowing.

If you are taking the rapidly-dissolving tablets, dissolve in the mouth with or without water as directed by your doctor or the product package.

Vitamin C (ascorbic acid) can decrease the amount of vitamin B12 you absorb. Avoid taking large doses of vitamin C within one hour before or after taking this product.

If your condition lasts or gets worse, or if you think you may have a serious medical problem, get medical help right away.

This product usually has no side effects. If you have any unusual effects, contact your doctor or pharmacist promptly.

If your doctor has directed you to use this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

If you have severe anemia, this medication may rarely cause low potassium levels in the blood (hypokalemia) as your body makes new red blood cells. Tell your doctor right away if any of these serious side effects occur:

• muscle cramps
• weakness
• irregular heartbeat

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking cyanocobalamin, tell your doctor or pharmacist if you are allergic to it; or to any form of vitamin B12; or to cobalt; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

If you have any of the following health problems, consult your doctor or pharmacist before using this medication:

• a certain eye disease (Leber's optic neuropathy)
• a certain blood disorder (polycythemia vera)
• gout
• iron or folic acid deficiency anemia
• low potassium blood levels (hypokalemia)

Cyanocobalamin taken by mouth should only be used if your body can properly absorb it. You may need a form of vitamin B12 that is injected or inhaled in the nose if you have any of the following health problems:

• pernicious anemia
• food absorption problems
• stomach/intestinal surgery (such as gastric bypass or bowel resection)
• stomach/intestinal disease (such as Crohn's disease, colitis, diverticulitis, pancreatic insufficiency)
• irradiation of the small bowel

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Cyanocobalamin is safe to use during pregnancy when taken in recommended doses. Higher doses should be used only when clearly needed. Discuss the risks and benefits with your doctor.

Cyanocobalamin passes into breast milk and is unlikely to harm a nursing infant when used in recommended doses. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

This medication may interfere with certain lab tests (such as intrinsic factor, blood tests for other types of anemia), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as vitamin B12 levels, complete blood count, blood potassium levels) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

Remember that it is best to get your vitamins and minerals from food whenever possible. Eat a well-balanced diet, and follow any dietary guidelines as directed by your doctor. Foods rich in vitamin B12 include meat, poultry, shellfish, eggs, milk, and other dairy products.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Different brands of this medication may have different storage needs. Check the product package for specific instructions on how to store your brand, or ask your pharmacist. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.