Pretreatment of infant formula with sodium polystyrene sulfonate : focus on optimal amount and contact time.

In pediatric patients at risk of hyperkalemia there are limited treatment or preventive alternatives for this electrolyte imbalance. Oral or rectal sodium polystyrene sulfonate (SPS) has several potential adverse effects, and dietary potassium restriction may compromise nutrition. Pretreatment of infant formula with SPS has been previously studied with promising efficacy. The optimal dosing and contact time has not been fully elucidated for this practice, nor have brand and generic products been compared. The present study aimed to evaluate the effectiveness of varying amounts of brand and generic SPS for the removal of potassium from formula after 1 and 24 hours. SPS was added to infant formula in four different amounts measured in milliliters to reflect how a parent or caregiver would measure this product at home. After 1 and 24 hours samples were withdrawn and potassium and sodium levels were measured. Potassium decreased in all samples, with the greatest reduction after the addition of 10 mL of SPS. Sodium levels increased in all pretreated samples to a greater extent than the potassium reduction. Contact time of either 1 or 24 hours did not impact the amount of potassium removed or the increase in sodium concentration. There were also no differences found between generic and brand SPS products. The effectiveness of SPS for formula pretreatment appears to have a plateau effect beyond the addition of 20 mL (16.47 g of brand name product, 19.5 g of generic product). This study demonstrates an effective protocol for pretreatment of formula.