Methylcobalamin is the active form of vitamin B12 that is used in adults alone or in combination with other vitamins as a dietary supplement. Vitamin B12 is important for the brain and nerves, and to produce red blood cells.

Methylcobalamin may also be used for purposes not listed in this medication guide.

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed. Do not use more of this product than is recommended on the label.

You may also consult the Office of Dietary Supplements of the NIH, or the USDA Nutrient Database of recommended daily allowances for more information.

Swallow the capsule whole and do not crush, chew, break, or open it.

Your dose needs may change if you switch to a different brand, strength, or form of methylcobalamin. Avoid medication errors by using exactly as directed on the label, or as prescribed by your doctor.

You must chew the chewable tablet before you swallow it.

Do not swallow a lozenge, disintegrating tablet, or sublingual tablet whole. Allow it to dissolve in your mouth without chewing. The sublingual tablet should be placed under your tongue.

You may need frequent blood tests, and your next dose may be delayed based on the results.

Store in original container at room temperature away from moisture, heat, and light.

You should not use methylcobalamin if you are allergic to vitamin B12 or cobalt.

Ask your doctor or pharmacist before taking methylcobalamin if you have any health problems.

Tell your doctor if you are pregnant or breastfeeding.

Do not give any herbal or health supplement to a child without medical advice.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid drinking large amounts of alcohol. Heavy drinking can make it harder for your body to absorb methylcobalamin.

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

Less serious side effects may be more likely, and you may have none at all.

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.

Do not take methylcobalamin without medical advice if you are using any of the following medications:

• oral diabetes medicine that contains metformin; or

• medicines that reduce stomach acid, such as cimetidine, omeprazole, lansoprazole, Nexium, Prevacid, Prilosec, Zantac, and others.

This list is not complete. Other drugs may affect methylcobalamin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.