Thrombocytopenia associated with sodium polystyrene sulfonate

: A 84-year-old man was admitted with diabetes mellitus, hypertension and chronic renal failure in September 1994. In October 1995, his renal function gradually worsened with hyperkalemia. Sodium polystyrene sulfonate (Kayexalate) was administered orally for the treatment of hyperkalemia. However, after 7 days from the start of Kayexalate therapy, thrombocytopenia progressed gradually, and 12 days later the initial platelet count of 20.7 x 10(4)/microliter decreased to 8.6 x 10(4)/microliter. This thrombocytopenia rapidly improved after cessation of Kayexalate administration. In December 1995, readministration of Kayexalate for the treatment of hyperkalemia induced thrombocytopenia again. Bone marrow aspiration biopsy revealed normal counts of nucleated cells and megakaryocytes with no increase in blasts. No other disorders which cause thrombocytopenia were seen in this patient. The complication of thrombocytopenia associated with Kayexalate has not been reported. This is the first reported case of thrombocytopenia caused by Kayexalate administration.