Probable chlorthalidone-induced hypokalemic rhabdomyolysis

Purpose

A case of hypokalemic rhabdomyolysis related to chlorthalidone use is reported

Case

A 52-year-old male was admitted to the hospital for acute onset generalized weakness and was found to have severe hypokalemia and rhabdomyolysis. The patient had been on chlorthalidone therapy with a dose increase from 25 mg daily to 50 mg daily 2 months prior to admission. Extensive workup ruled out neurologic, rheumatologic, and endocrinologic causes of hypokalemia. In the absence of other causes, it was determined that the patient was experiencing a severe presentation of chlorthalidone-induced hypokalemia resulting in rhabdomyolysis. The patient’s rhabdomyolysis and weakness improved with aggressive potassium correction, and potassium wasting eventually resolved with discontinuation of chlorthalidone.

Conclusion

Although mild hypokalemia is a known side effect of thiazide and thiazide-like diuretics, health care providers should be aware of the possibility of severe manifestations of this adverse reaction, even at relatively small dose increases.