Drugs List

Therapeutic Indications

Uses

Macrocytic anaemia due to B12 deficiency: prophylaxis
Macrocytic anaemia with neurological involvement: Treatment
Macrocytic anaemia without neurological involvement: Treatment
Schilling test

Contraindications

Toxic amblyopia

Precautions and Warnings

Hypokalaemia

Folate deficiency: Indiscriminate administration may mask true diagnosis
Confirm vitamin B12 deficiency as cause of megaloblastic anaemia
Exclude folate deficiency as cause of megaloblastic anaemia
Monitor blood values before and during treatment
Monitor serum potassium on initiation as hypokalaemia can occur
Monitor neurological function

Doses of cyanocobalamin above 10 micrograms may produce an incomplete haematological response in patients with folate deficiency and indiscriminate administration may mask the correct diagnosis.

Platelet count should be monitored during the first weeks of use in megaloblastic anaemia due to the possible occurrence of reactive thrombocytosis.

Pregnancy and Lactation

Pregnancy

Cyanocobalamin can be used during breastfeeding.

Only indicated for use in megaloblastic anaemia in pregnancy if vitamin B12 deficiency has been demonstrated.

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 ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Lactation

Cyanocobalamin can be used during pregnancy.

Cyanocobalamin is secreted into breast milk, but secretion is unlikely to harm the infant and may be beneficial if mother and child are vitamin B12 deficient.

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 https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1

Side Effects

Acne-like eruptions
Anaphylaxis
Arrhythmias
Bullous eruption
Chills
Dizziness
Fever
Hot flushes
Hypersensitivity reactions
Hypokalaemia
Induration (injection site)
Injection site reactions
Itching
Local pain (intramuscular injection site)
Malaise
Nausea
Necrosis (injection site)
Rash
Thrombocytosis
Tremor

Presentation

Solution for injection containing cyanocobalamin

Drugs List

Therapeutic Indications

Uses

Macrocytic anaemia due to B12 deficiency: prophylaxis
Macrocytic anaemia with neurological involvement: Treatment
Macrocytic anaemia without neurological involvement: Treatment
Schilling test

Dosage

Adults

Elderly

Children

Contraindications

Toxic amblyopia

Precautions and Warnings

Hypokalaemia

Folate deficiency: Indiscriminate administration may mask true diagnosis
Confirm vitamin B12 deficiency as cause of megaloblastic anaemia
Exclude folate deficiency as cause of megaloblastic anaemia
Monitor blood values before and during treatment
Monitor serum potassium on initiation as hypokalaemia can occur
Monitor neurological function

Doses of cyanocobalamin above 10 micrograms may produce an incomplete haematological response in patients with folate deficiency and indiscriminate administration may mask the correct diagnosis.

Platelet count should be monitored during the first weeks of use in megaloblastic anaemia due to the possible occurrence of reactive thrombocytosis.

Pregnancy and Lactation

Pregnancy

Cyanocobalamin can be used during breastfeeding.

Only indicated for use in megaloblastic anaemia in pregnancy if vitamin B12 deficiency has been demonstrated.

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 ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Lactation

Cyanocobalamin can be used during pregnancy.

Cyanocobalamin is secreted into breast milk, but secretion is unlikely to harm the infant and may be beneficial if mother and child are vitamin B12 deficient.

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 https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1

Side Effects

Acne-like eruptions
Anaphylaxis
Arrhythmias
Bullous eruption
Chills
Dizziness
Fever
Hot flushes
Hypersensitivity reactions
Hypokalaemia
Induration (injection site)
Injection site reactions
Itching
Local pain (intramuscular injection site)
Malaise
Nausea
Necrosis (injection site)
Rash
Thrombocytosis
Tremor

Overdosage

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 ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Further Information

Last Full Review Date: April 2016

Reference Sources

Joint Formulary Committee. British National Formulary. 71st ed. London: BMJ Group and Pharmaceutical Press; 2016.

Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.

Summary of Product Characteristics: Cytamen Injection 1000mcg. UCB Pharma Limited. Revised January 2015