Probable chlorthalidone-induced hypokalemic rhabdomyolysis

Objective: A case of hypokalemic rhabdomyolysis related to chlorthalidone use is reported SUMMARY: 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 25mg daily to 50mg daily two 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.