Sodium Phosphate

Drug Levels and Effects:

Summary of Use during Lactation:

Phosphate is a normal constituent of breastmilk. Phosphate concentrations have not been measured in breastmilk after large maternal doses ofsodiumphosphate, such a 30 gram oral dose for pre-procedural bowel evacuation. However, the added phosphate in breastmilk is likely to be only about 130 mg over 24 hours in this situation. The increase from a typical dose of a rectal enema would be considerably less than this amount. Breastmilksodiumconcentration is tightly regulated, and will not be affected. It is probably not necessary to suspend breastfeeding after the use of oralsodiumphosphate solutions given once or twice for bowel evacuation before a procedure, but if there is concern, suspension of nursing for 24 hours after a dose should result in negligible increase in phosphate ingestion by the infant. Use of a phosphate rectal enema by a nursing mother would require no special precautions.

Drug Levels:

Phosphate is a normal constituent of breastmilk.[1][2] Infants normally receive about 130 mg of inorganic phosphate daily from breastmilk.[2]

Maternal Levels.

Administration of a 30 gram dose of oralsodiumphosphate solution (e.g., Visicol) approximately doubles the maternal serum phosphate concentration, with serum concentrations returning to baseline about 24 hours after the dose.[3][4] Assuming breastmilk phosphate concentration also doubles, the increased phosphate dose to the infant would be only 130 mg for one day.

Administration of a phosphate enema (2 Fleet Enemas, containing a total of 14 grams ofsodiumphosphate dibasic and 38 grams ofsodiumphosphate monobasic) to 33 subjects increased serum phosphate by an average of about 25% (range 0.1 to 2.5 mg/dL).[5] In one other patient, a phosphate enema (Practo Clyss 120, containing a total of 7.2 grams ofsodiumphosphate dibasic and 19.2 grams ofsodiumphosphate monobasic) increased serum phosphate by 35% (by 0.8 mmol/L) after a single dose.[6]

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Relevant published information was not found as of the revision date.

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.


1. Kent JC, Arthur PG, Retallack RW, Hartmann PE.Calcium, phosphate and citrate in human milk at initiation of lactation. J Dairy Res. 1992;59:161-7. PMID:1613174
2. Allen JC, Keller RP, Archer P, Neville MC. Studies in human lactation: milk composition and daily secretion rates of macronutrients in the first year of lactation. Am J Clin Nutr. 1991;54:69-80. PMID:2058590
3. Ehrenpreis ED. Increased serum phosphate levels andcalciumfluxes are seen in smaller individuals after a single dose ofsodiumphosphate colon cleansing solution: a pharmacokinetic analysis. Aliment Pharmacol Ther. 2009;29:1202-11. PMID:19298584
4. Visicol package insert. Salix Pharmaceuticals, Inc. December 2010.
5. Schuchmann GD, Barcia PJ. Phosphate absorption from fleet enemas in adults. Curr Surg. 1989;46:120-2. PMID:2736963
6. Rimensberger P, Schubiger G, Willi U. Connatal rickets following repeated administration of phosphate enemas in pregnancy: a case report. Eur J Pediatr. 1992;151:54-6. PMID:1728548

Substance Identification:

Substance Name:


CAS Registry Number:

7558-79-4; 7558-80-7

Drug Class:

  • Cathartics

  • Electrolyte

  • Gastrointestinal Agents

  • Minerals

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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