Australian Approved Name (AAN): Magnesium phosphate pentahydrate
Common names and synonyms: Magnesium phosphate; Magnesium phosphate – tribasic pentahydrate
Superseded AAN: Magnesium phosphate
Organic/Inorganic: Inorganic
Molecular formula: Mg3P2O8.5H2O
Molecular weight: 352.93
Conversions (% magnesium): 20.66 (% phosphorus): 17.55
TGA (eBS) allowable range for conversions: The amount of magnesium in the active ingredient should be calculated based on the molecular weight of magnesium phosphate pentahydrate.
RDI for Magnesium as per NHMRC:
Infants – 0-6 months – 30mg/day (AI)
Infants – 7-12 months – 75mg/day (AI)
Children – 1-3 years – 80mg/day
Children – 4-8 years – 130mg/day
Boys – 9-13 years – 240mg/day
Boys – 14-18 years – 410mg/day
Girls – 9-13 years – 240mg/day
Girls – 14-18 years – 360mg/day
Men – 19-30 years – 400mg/day
Men – 31->70 years – 420mg/day
Women – 19-30 years – 310mg/day
Women – 31->70 years – 320mg/day
Pregnancy – 14-18 years – 400mg/day
Pregnancy – 19-30 years – 350mg/day
Pregnancy – 31-50 years – 360mg/day
Lactation – 14-18 years – 360mg/day
Lactation – 19-30 years – 310mg/day
Lactation – 31-50 years – 320mg/day
Mandatory components: Magnesium
Warnings and Restrictions: The requirements specified in paragraphs (a) to (c) below apply to a medicine that contains the ingredient:
(a) Magnesium is a mandatory component of magnesium phosphate pentahydrate.
(b) When used in a medicine:
(i) with an oral route of administration;
(ii) not indicated for laxative (or related) use; and
(iii) where the maximum recommended daily dose for:
(A) children aged between 1 and 3 years (inclusive) provides 65 mg or more total magnesium from inorganic magnesium salts;
(B) children aged between 4 and 8 years (inclusive) provides 110 mg or more total magnesium from inorganic magnesium salts; or
(C) individuals aged 9 years or older provides 350 mg or more total magnesium from inorganic magnesium salts;
the following warning statement is required on the medicine label:
LAX6 – Contains magnesium, which may have a laxative effect or cause diarrhoea (or words to that effect).
(c) When the route of administration is oral, the medicine must not be directed for use in infants younger than 12 months of age.
Allowable purpose of the ingredient: Active. Excipient. Homeopathic.
TGA reference: United States Pharmacopeia_(Incorporating the National Formulary) (modified)