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Hydroxocobalamin solution for injection

Updated 2 Feb 2023 | Vitamin B12


Solution for injection containing hydroxocobalamin

Drugs List

  • COBALIN-H 1mg/1ml injection
  • hydroxocobalamin 1mg/ml injection
  • NEO-CYTAMEN 1mg/1ml injection
  • Therapeutic Indications


    Leber's optic atrophy
    Macrocytic anaemia due to B12 deficiency: prophylaxis
    Macrocytic anaemia with neurological involvement: Treatment
    Macrocytic anaemia without neurological involvement: Treatment
    Tobacco amblyopia

    Unlicensed Uses

    Congenital transcobalamin II deficiency
    Methylmalonic acidaemia



    Addisonian pernicious anaemia and other macrocytic anaemias without neurological complications
    Initial dose: 250 to 1000 micrograms on alternate days for 7 to 14 days, followed by 250 micrograms weekly until blood count returns to normal.
    Maintenance dose: 1000 micrograms every two to three months thereafter.

    Addisonian pernicious anaemia and other macrocytic anaemias with neurological complications
    Initial dose: 1000 micrograms on alternate days.
    Maintenance dose: 1000 micrograms every two months thereafter.

    Prophylaxis of macrocytic anaemias associated with Vitamin B12 deficiency
    1000 micrograms every two or three months.

    Tobacco amblyopia and Leber's optic neuropathy
    Initial dose: 1000 micrograms daily for two weeks, then twice weekly.
    Maintenance dose: 1000 micrograms every three months or, if required, as frequently as monthly.


    For licensed doses in children aged 1 month to 18 years (See Dosage; Adult).

    Congenital transcobalamin II deficiency (unlicensed)
    Children aged 1 month to 18 years
    Initial dose: 1mg three times weekly. Dose may be reduced to 1mg once weekly or as appropriate, after one year of therapy.

    Homocystinuria and methylmalonic acidaemia (unlicensed)
    Initial dose: 1mg daily for 5 to 7 days.
    Maintenance dose: Up to 1mg once or twice weekly, titrated according to response.
    In patients with methylmalonic acidaemia responding well to intramuscular injection, consider oral administration at a dose of 5mg to 10mg once or twice weekly.


    Congenital transcobalamin II deficiency (unlicensed)
    Initial dose: 1mg three times weekly. Dose may be reduced to 1mg once weekly or as appropriate, after one year of therapy.


    None known

    Precautions and Warnings


    Folate deficiency: Indiscriminate administration may mask true diagnosis
    Chloramphenicol treated patients may respond poorly
    Confirm diagnosis of vitamin B12 deficiency before initiating treatment
    Exclude folate deficiency as cause of megaloblastic anaemia
    Monitor serum potassium on initiation as hypokalaemia can occur
    Monitor haematological parameters regularly throughout treatment
    Monitor platelet count for thrombocytosis in first weeks of treatment
    Antibodies to ingredient may develop
    Most antibiotics invalidate Vitamin B12 assays by microbiological technique

    Pregnancy and Lactation


    Use hydroxocobalamin with caution during pregnancy.

    Hydroxocobalamin supplementation is not routinely needed when pregnant. Anaemia caused by a vitamin B12 deficiency should be treated during pregnancy (Schaefer, 2015). Severe maternal vitamin B12 deficiency during pregnancy may lead to subsequent infertility and poor pregnancy outcome, however less severe deficiencies are not thought to be harmful to mother of foetus (Briggs, 2015).

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Hydroxocobalamin is considered safe for use during breastfeeding.

    Hydroxocobalamin is secreted in breast milk but it is not expected to cause harm in the infant.

    There have been reports of megaloblastic anaemia in infants nursing from vitamin B12 deficient mothers. The American Academy of Paediatrics classifies vitamin B12 as compatible with breastfeeding (Briggs, 2015).

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Acne-like eruptions
    Arrhythmias secondary to hypokalaemia
    Bullous eruption
    Hot flushes
    Hypersensitivity reactions
    Injection site reactions
    Sensory disturbances


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: June 2017

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.

    Summary of Product Characteristics: Cobalin-H injection. Concordia International - formerly AMCo. Revised February 2018.
    Summary of Product Characteristics: Hydroxocobalamin 1mg in 1ml solution for injection. Auden Mckenzie (Pharma Division) Ltd (a subsidiary of Actavis PLC). Revised Augsut 2017.
    Summary of Product Characteristics: Hydroxocobalamin Injection BP 1mg/ml. Concordia International - formerly AMCo. Revised March 2018.
    Summary of Product Characteristics: Neo-Cytamen 1000 micrograms/ml solution for injection. RPH Pharmaceuticals AB. Revised January 2015.

    NICE - Evidence Services Available at: Last accessed: 12 Novemeber 2018

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