Reduction of serum calcium by sodium sulfonated polystyrene resin.

Sodium resin has been clinically administered against hyperkalemia widely, but its effects of lowering the serum calcium has never been documented. In our study, 7 patients with chronic renal failure were chosen at random to take sodium resin 30 g per day for 3 days. The sodium resin not only lowered the serum potassium level (p less than 0.05) but also brought down the level of serum calcium (p less than 0.05). The reduced ability of patients with chronic renal failure to absorb calcium from the gastrointestinal tract is well recognized, so its effects of lowering calcium will be more likely to aggravate the serum calcium imbalance further. If sodium resin has to be used for the maintainance of serum potassium in patients with chronic renal failure the serum calcium should be monitored closely in order to lighten the osteodystrophy and secondary hyperparathyroidism.