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Hydroxocobalamin injection

Cobalin-H, Neo-Cytamen

Hydroxocobalamin is used to treat some types of anaemia.

It is given by injection into a muscle.

Treatment with hydroxocobalamin is usually lifelong.

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About hydroxocobalamin

Type of medicine

Vitamin B12 replacement

Used for

Anaemia caused by lack of vitamin B12, and some rare eye conditions

Also called

Cobalin-H®; Neo-Cytamen®

Available as


The most common cause of vitamin B12 deficiency in the UK is a condition called pernicious anaemia. This is a condition where insufficient amounts of vitamin B12 are absorbed into your body from the food you eat. This can be because you are not able to absorb it properly, or because you have had surgery which has removed part of your digestive system. This type of anaemia is easily treated by having regular injections of hydroxocobalamin, which is a form of vitamin B12.

Hydroxocobalamin is also occasionally used for some rare eye conditions.

Before having hydroxocobalamin

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start having hydroxocobalamin injections it is important that your doctor knows:

  • If you are pregnant or breastfeeding. (Hydroxocobalamin is not known to be harmful to an unborn baby or while breastfeeding, but nevertheless you should let your doctor know about this.)

  • If you have ever had an allergic reaction to a medicine.

  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

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How your hydroxocobalamin is given

  • Hydroxocobalamin will usually be given to you by your doctor or nurse. It will be given by injection into a muscle.

  • When you first start treatment, you will need to have an injection every 2-3 days. This is to top up the store of vitamin B12 in your body. After a few weeks, you will only need to have one injection every 2-3 months. Your doctor will tell you when to arrange an appointment for you to have these injections. If ever you miss an appointment, you should contact your doctor's surgery to make another appointment as soon as possible so that you receive your injections on time.

Getting the most from your treatment

  • Before you start this treatment, ask to read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about treatment with hydroxocobalamin.

  • Try to keep your regular doctor's appointments so that your progress can be checked. You may need to have some blood tests from time to time, particularly at the beginning of your treatment. The tests will check that the treatment is working, and will also check on the amount of potassium in your blood, as this may drop a little initially.

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Can hydroxocobalamin cause problems?

Along with their useful effects, all medicines can cause unwanted side-effects although not everyone experiences them. The table below lists some of the most common ones associated with hydroxocobalamin injections. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve in the first few days after having the injection, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Hydroxocobalamin side-effects

What can I do if I experience this?

Feeling sick (nausea)

Stick to simple meals - avoid rich or spicy food


Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, speak with your doctor

Feeling dizzy

If this happens, do not drive and do not use tools or machines until you feel well again

High temperature (fever), rash, itching or pain where you were injected

Let your doctor or nurse know about these

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor, nurse or pharmacist.

How to store hydroxocobalamin

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

If you are having an operation or dental treatment tell the person carrying out the treatment which medicines you are taking.

If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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