Daptomycin-induced hyperkalemia in a patient with normal renal function.

PURPOSE: A case of episodic hyperkalemia associated with daptomycin administration is reported. SUMMARY: A 46-year-old African-American woman was hospitalized for treatment of a shoulder abscess. Initially treated with i.v. vancomycin, the patient was switched to daptomycin 9 mg/kg i.v. (500 mg daily) after three days. On day 10 of daptomycin therapy, she was noted to have a serum potassium concentration of 5.4 meq/L, with an increase to 6.1 meq/L on day 11. Reversal of hyperkalemia was achieved with oral sodium polystyrene sulfonate and other agents, and daptomycin was withheld for one day, during which time the patient's serum potassium level normalized. One day after daptomycin therapy was resumed at a lower dose (7 mg/kg), the potassium concentration increased again (to 5.5 meq/L). With a further dosage reduction and continued administration of sodium polystyrene sulfonate, the patient completed the full course of daptomycin therapy. There was a close temporal relationship between daptomycin administrations and the serum potassium fluctuations; other potential causes of hyperkalemia were ruled out. Evaluation of this case using the algorithm of Naranjo et al. yielded a score of 6, indicating that the serum potassium elevations probably constituted an adverse reaction to daptomycin. A literature search identified no other reports of hyperkalemia associated with daptomycin use in a patient with normal renal function. CONCLUSION: A 46-year-old women with normal renal function developed hyperkalemia after receiving high-dose daptomycin therapy. The potassium levels normalized when daptomycin was withheld but increased again when the patient was rechallenged with the drug.