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Sodium phosphate with potassium dihydrogen phosphate parenteral

Updated 2 Feb 2023 | Phosphate supplements


Solution for infusion containing sodium phosphate and potassium dihydrogen phosphate.

Drugs List

  • POLYFUSOR NA PHOSPHATES infusion 500ml bottle
  • sodium phosphate with potassium dihydrogen phosphate 2.875g+647.5mg/500ml infusion 500ml bottle
  • Therapeutic Indications




    Dosage must be adjusted to the condition of the patient, the fluid, electrolyte and acid-base balance.


    Moderate hypophosphataemia (serum inorganic phosphate 0.5mmol/L to 0.7mmol/L)

    0.1 to 0.2mmol phosphate/kg of bodyweight (equivalent to 1ml to 2ml Polyfusor Phosphates/kg bodyweight) over 6 to 12 hours.

    Severe hypophosphataemia (serum inorganic phosphate below 0.5mmol/L)

    0.2 to 0.5mmol phosphate/kg of bodyweight (equivalent to 2ml to 5ml Polyfusor Phosphates/kg bodyweight) over 6 to 12 hours.

    A maximum dose of 50mmol per infusion should not be exceeded.
    Not more than 15mmol phosphate/hour should be given.


    Children aged over 12 years
    (See Dosage; Adult)

    The following alternative dosing schedule may be suitable:
    Children aged 12 to 18 years: 0.4mmol/kg phosphate daily, by slow intravenous infusion adjusted as necessary.
    Children aged 2 to 12 years (unlicensed): 0.4mmol/kg phosphate daily, by slow intravenous infusion adjusted as necessary.
    Children aged 1 month to 2 years (unlicensed): 0.7mmol/kg phosphate daily, by slow intravenous infusion adjusted as necessary.

    Dilute injection with sodium chloride 0.9% or 0.45% or glucose 5% or 10%. Administration rate of phosphate should not exceed 0.05mmol/kg/hour. In emergencies in intensive care faster rates may be used. Seek specialist advice.


    The following unlicensed dosing schedule may be suitable in neonates:

    1mmol/kg phosphate daily, adjusted as necessary.


    Renal impairment

    Precautions and Warnings

    Children under 13 years
    Peripheral oedema
    Adrenal insufficiency
    Cardiac disorder
    Congestive cardiac failure
    Diabetes mellitus
    Pulmonary oedema
    Severe burn

    Administer infusion slowly
    Precipitate may form when phosphates added to calcium or magnesium solution
    Rapid injection may be cardiotoxic
    Monitor acid-base balance
    Monitor ECG
    Monitor fluid balance
    Monitor renal function
    Monitor serum electrolytes

    Pregnancy and Lactation


    Use intravenous sodium phosphate and potassium dihydrogen phosphate with caution 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 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 ( ).


    Use intravenous sodium phosphate and potassium dihydrogen phosphate with caution during breastfeeding.

    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

    Acute renal failure
    Cardiac arrest
    Cardiac arrhythmias
    Decreased lacrimation
    Extraskeletal calcification
    Heart block
    Local pain (injection site)
    Muscle weakness
    Organ damage
    Paraesthesia in extremities
    Phlebitis (injection site)
    Respiratory failure


    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: November 2013

    Reference Sources

    Summary of Product Characteristics: Phosphates as Polyfusor NA and Freeflex. Fresenius Kabi Ltd. Revised August 2006.

    NICE Evidence Services Available at: Last accessed: 7 September 2017

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