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Sodium acid phosphate oral

Updated 2 Feb 2023 | Phosphate supplements


Oral formulations of sodium acid phosphate anhydrous.

Drugs List

  • PHOSPHATE-SANDOZ effervescent tablet
  • sodium acid phosphate 1.936g effervescent tablet
  • Therapeutic Indications


    Rickets - hypophosphataemic - vitamin D resistant

    Hypercalcaemia associated with such conditions as hyperparathyroidism, multiple myelomatosis and malignancy.

    Hypophosphataemia associated with vitamin D resistant rickets and vitamin D resistant hypophosphataemic osteomalacia.


    Effervescent tablets containing 1.936g of anhydrous sodium acid phosphate equivalent to phosphorus 500mg (phosphate 16.1mmol).

    Dosage should be adjusted to suit individual requirements.


    Up to 6 tablets per day.

    Vitamin D resistant hypophosphataemic osteomalacia
    4 to 6 tablets daily.


    Children under 5 years
    Up to 3 tablets per day.

    Vitamin D resistant rickets
    2 to 3 tablets daily.

    The following alternative dose may be suitable:
    Children aged 5 to 18 years
    2 to 3mmol/kg daily in 2 to 4 divided doses. Dose should be adjusted as necessary to a maximum 97mmol per day.

    Children aged 1 month to 5 years
    2 to 3mmol/kg daily in 2 to 4 divided doses. Dose should be adjusted as necessary to a maximum 48mmol per day. Dose can be taken as a supplement in breast milk although solubility is limited to 1.2mmol in 100ml if calcium is also added.


    Hypophosphataemia, Hypophosphataemic rickets & Osteomalacia (unlicensed)
    1mmol/kg daily in 1 to 2 divided doses.

    The dose can be taken as a supplement in breast milk, however, solubility is limited to 1.2mmol in 100ml if calcium is also added.


    Hereditary fructose intolerance

    Precautions and Warnings

    Restricted sodium intake
    Congestive cardiac failure
    Glucose-galactose malabsorption syndrome
    Renal impairment

    Sodium content of effervescent preparation may be significant
    Contains polyethylene glycol
    Preparation contains sucrose
    Indigestion remedies should not be taken at the same time
    Monitor serum electrolytes before and during treatment
    During long term use make clinical examinations at regular intervals
    Monitor patients with renal impairment
    Monitor serum phosphate levels
    Monitor serum potassium and calcium
    Consider dose reduction for subsequent doses if severe diarrhoea occurs
    Excessive doses may cause metastatic calcification

    The content of sodium (20.4mmol) and potassium (3.1mmol) in each tablet should be taken into account in patients with renal impairment associated with hypercalcaemia and in cases where restricted sodium intake is required.

    Pregnancy and Lactation


    Use sodium acid phosphate with caution during pregnancy.

    The safety of oral phosphate therapy during pregnancy has not been formally established; however it has been used for many years without any apparent ill effects.

    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 ( ).


    Use sodium acid phosphate with caution during breastfeeding.

    The safety of oral phosphate therapy during breast feeding has not been formally established.

    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

    Gastro-intestinal 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: January 2019

    Reference Sources

    Summary of Product Characteristics: Phosphate Sandoz Effervescent Tablets. HK Pharma Ltd. Revised July 2015.

    NICE Evidence Services Available at: Last accessed: 17 January 2019

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