Movilli E, et al. - Researchers evaluated serum potassium (sK) before and after starting angiotensin-converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB) therapy in anuric patients on chronic hemodialysis treatment (HD). These patients showed a higher risk for hyperkalemia in relation to ACEi/ARB therapy. A decrease in the proportion of patients with normal sK concentrations from 82% to 29% and an increase from 18% to 52% in the proportion of patients with mild hyperkalemia was seen. In 19% of patients, severe hyperkalemia required that ACEi/ARB therapy be interrupted. Practicing great caution is recommended in using of this class of drugs in HD patients.