Cyanocobalamin is an active form of Vitamin B12. It is essential for healthy nerves and red blood cells, as well as DNA production. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.

What is this medication for?

Cyanocobalamin is an active form of Vitamin B12. It is essential for healthy nerves and red blood cells, as well as DNA production.

Cyanocobalamin on its own is used to treat or prevent Vitamin B12 deficiency in certain groups of people like:

• People with megaloblastic anaemia (abnormally large red blood cells)
• People with autoimmune disease (e.g. pernicious anaemia or atrophic gastritis where there is insufficient intrinsic factor in the stomach needed for vitamin B12 absorption)
• People with had stomach or intestinal surgery &/or digestive system disorders

People with peripheral neuropathy (a nerve disorder)

• Vegans or vegetarians
• Elderly

Cyanocobalamin is also available in various combinations (e.g. B1, B6 & B12) to help manage symptoms of nerve problems such as numbness or tingling in the hands or feet.

How should I take or use this medication?

Cyanocobalamin is available in tablet or injection form.

• Take this medication as prescribed by your healthcare professional
• Do not stop taking your medication without checking with your healthcare professional.
• You may take this medication with or without food. 

This medication should usually be taken in the morning, as they may help with energy levels. If it is taken at night or close to bedtime, it might cause wakefulness or alertness.

What should I do if I forget to take or use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose. 

What precautions should I take when taking or using this medication?

Inform your healthcare professional if: 

You are allergic to this medication or any of the other ingredients of this medication.

• You are taking any other medications, including supplements, traditional medications and herbal remedies.

What are some common side effects of this medication?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Inform your healthcare professional if you have any side effects that bother you or do not go away, such as

• Headache

Diarrhoea, nausea, or vomiting

• May take after meals if you experience above side effects

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following: 

• Swollen face/eyes/lips/tongue
• Difficulty in breathing

Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How do I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.

Disclaimer

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on June 2025