Can you take sevelamer while breastfeeding?

What LactMed says

The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.

Because sevelamer is not orally absorbed, sevelamer does not reach the breastmilk or adversely affect the breastfed infant after maternal administration. A suspension of sevelamer has been added directly to breastmilk to lower the phosphorus concentration of milk. This could be a useful maneuver for breastmilk use in infants with renal impairment; however, clinical use has not been reported. In addition to lowering average phosphorus content by 65% to over 80%, the calcium content of breastmilk was reduced by almost as much and the casein content also decreased somewhat. With sevelamer hydrochloride, the chloride content increased by 60% and the pH changed from 6.8 to 7.8, although pH appears to rebound over time. Addition of large amounts of sevelamer to artificial formula also lowers the copper, magnesium, manganese, potassium, sulfur and zinc concentrations by about 20%. Similar reductions might occur with breastmilk.

Quoted from Sevelamer — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised June 21, 2021.