Aim: The objective of this study was to determine the incidence and risk factors of hyperkalemia associated with trimethoprim-sulfamethoxazole (TMP-SMX) in the intensive care unit (ICU).
Study design: A single-center, retrospective observational study.
Materials and Methods: The study population consisted of patients who received TMP-SMX in the ICU. Patients were categorized into two groups based on the level of serum potassium: the group with hyperkalemia and the group without hyperkalemia.
Results: The incidence of hyperkalemia in the patients receiving TMP-SMX in ICU was 49% (25/51). Hyperkalemia occurred 6.2±3.8 days after the beginning of TMP-SMX treatment. Baseline serum potassium level determined as an independent risk factor for hyperkalemia (p<0.009). The optimal cut-off value of baseline serum potassium to predict hyperkalemia associated with TMP-SMX was 3.55 mEq/L.
Conclusion: Potassium levels should be closely monitored, especially in the first week of TMP treatment, in critically ill patients. Even if the baseline potassium level is within normal limits, care should be taken in terms of hyperkalemia. In addition, even if hyperkalemia is mild, potassium-lowering therapeutic approaches may be necessary.