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Updated 2 Feb 2023 | Selenium


Oral solution containing 100micrograms/2ml selenium in the form of sodium selenite pentahydrate.

Oral solution containing 500micrograms/10ml selenium in the form of sodium selenite pentahydrate.

Drugs List

  • SELENASE 100microgram/2ml oral solution
  • SELENASE 500microgram/10ml oral solution
  • selenium 100microgram/2ml oral solution
  • selenium 500microgram/10ml oral solution
  • Dosage


    100 to 200micrograms selenium daily. If necessary this dose can be increased to 500micrograms daily.


    Initial dose

    2 micrograms/kg body weight/day at therapy onset.

    Maintenance dose

    1 microgram/kg body weight/ day.

    Maximum daily doses for children on long term treatment

    Children aged 1 to 3 years - maximum of 60 micrograms/day
    Children aged 4 to 6 years - maximum of 90 micrograms/day
    Children aged 7 to 10 years - maximum of 130 micrograms/day
    Children aged 11 to 14 years - maximum of 200 micrograms/day
    Children aged 15 to 17 years - maximum of 250 micrograms/day

    Patients with Renal Impairment

    No studies have been carried out on dosage adjustment in patients with renal impairment.

    Patients with Hepatic Impairment

    No studies have been carried out on dosage adjustment in patients with hepatic impairment.


    For oral administration.

    The liquid should be held in the mouth for 30-60 seconds before swallowing.

    For measuring a children's dose of less than 1 ml oral solution approximately 5 ml oral solution is placed in the measuring cup and the needed volume is drawn up with the enclosed pipette.



    Precautions and Warnings

    Selenium levels in whole blood or serum should be determined in order to monitor the success of treatment.

    The absorption of selenium may be reduced by ascorbic acid. These two substances should be administered at least 4 hours apart.

    Pregnancy and Lactation


    Adverse events are not expected when administered during pregnancy.

    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 14-17 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 ( ).


    Selenium is excreted in breast milk but is not thought to exert adverse effects on the suckling infant.

    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


    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 ( ).

    Reference Sources

    British National Formulary, 63rd Edition (2012) Pharmaceutical Press, London.

    BNF for Children (2011-2012) Pharmaceutical Press, London.

    Summary of Product Characteristics: Selenase 100/500 microgram oral solution. Biosyn Arzneimittel GmbH. Revised August 2011.

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