Polystyrene sulfonates

Uses

Polystyrene sulfonic acid has been used as sodium, potassium, and calcium salts. Sodium polystyrene sulfonate has been used to treat hyperkalemia in patients with renal insufficiency and as an adjuvant during hemodialysis. It can be given orally or rectally in all age groups [ ]. It has also been added to feeding formulae and nutritional supplements to reduce their potassium contents and so prevent hyperkalemia; however, the reduction in potassium content was more than balanced by a concomitant increase in sodium content, presumably because of exchange of the sodium with calcium and magnesium [ , ].

Potassium polystyrene sulfonate has been used to treat hypercalciuria and renal calculi. Calcium polystyrene sulfonate has been used to treat hyperkalemia, particularly in patients who cannot tolerate the extra sodium that would be provided by the sodium salt.

Observational studies

A confection containing sodium polystyrene sulfonate resin 5.0 g per piece was used to treat six patients on chronic dialysis with predialysis serum potassium concentrations of 5.2 mmol/l or more [ ]. Over 2 weeks the mean serum potassium fell by 0.7 mmol/l. However, the effectiveness of sodium polystyrene sulfonate in lowering serum potassium concentrations in patients with renal insufficiency has been questioned [ ]. A cathartic alone (phenolphthalein) in six patients caused an average fecal potassium output of 54 mmol. The addition of sodium polystyrene sulfonate had no further significant effect on total potassium output. With placebo the average serum potassium concentration increased slightly (0.4 mmol/l) during 12 hours. This rise was attenuated by sodium polystyrene sulfonate, perhaps in part because of extracellular volume expansion caused by the absorption of sodium. Phenolphthalein was associated with a slight rise in serum potassium concentration (similar to placebo), perhaps because of extracellular volume contraction produced by a sodium-rich diarrhea and acidosis secondary to bicarbonate loss. None of the regimens reduced the serum potassium concentration, compared with baseline.

Respiratory

Pneumonitis has been reported in a woman taking sodium polystyrene sulfonate [ ].