Effect of three laxatives and a cation exchange resin on fecal sodium and potassium excretion

Effectiveness of Sodium Polystyrene Sulfonate for Short-Term Treatment of Hyperkalemia

“…The researchers observed a mean reduction in serum potassium of 1.0 mmol/L over 24 h, and this study became the main supporting evidence for the use of SPS in hyperkalemia, despite its small sample size, concomitant interventions, and open-label design. 12 Since 1961, there have been 2 prospective randomized studies evaluating SPS, 13,14 which showed no benefit, and one retrospective observational study 15 that did show a benefit. In the first randomized crossover trial of SPS, published in 1995, 14 9 healthy participants were treated with 60 g of sorbitol with or without 100 mmol SPS.…”

“…12 Since 1961, there have been 2 prospective randomized studies evaluating SPS, 13,14 which showed no benefit, and one retrospective observational study 15 that did show a benefit. In the first randomized crossover trial of SPS, published in 1995, 14 9 healthy participants were treated with 60 g of sorbitol with or without 100 mmol SPS. Each participant was then given 40 mEq potassium IV and 23 mEq potassium via food.…”

Damned If You Do, Damned If You Don't

“…Excretion also depends on extracellular potassium and sodium concentrations and colonic transit time of the resin. The studies of stool potassium excretion described above showed that SPS functioned at approximately 33% efficiency (8,15). Efficiency could be reduced by normokalemia in the subjects, and the large amount of sodium excreted in the stool due to the action of the cathartic.…”

“…If there are no ECG changes, and potassium elevation is moderate, excretion can be increased using SPS or diuretics, and the source of excess potassium (either by way of the diet or inhibition of excretion) corrected. Because the effects of SPS are delayed for at least 2 hours (peaking at 4 to 6 hours) (4,8), it is not useful for acute potassium control. The only other "excretory" modalities available are dialysis and loop diuretics, both of which have limitations and potential side effects, and like SPS, may take hours to have an effect.…”

“…In a stool balance study in nine healthy normokalemic subjects, 30 g of SPS given with cathartics effectively bound and removed potassium in the stool within 12 hours, peaking at approximately 4 to 6 hours. Much of the potassium removed was due to cathartic-induced diarrhea; however, the addition of SPS significantly increased potassium content in the insoluble portion of stool-indicating that potassium was bound to SPS and excreted (8). All of the subjects received intravenous potassium replacement to maintain normal serum potassium.…”