Loop diuretics are K⁺-sparing in the presence of a low-Na⁺, high-K⁺ diet

Under most conditions, loop diuretics are K⁺-wasting, requiring potassium supplementation. In this issue, Wang and colleagues demonstrate that in mice fed a low-Na⁺, high-K⁺ diet, loop diuretics, in contrast, are K⁺-sparing. This observation suggests that possible elevations in plasma K⁺ should be monitored when using a loop diuretic with a low-Na⁺, high-K⁺ diet, particularly when in combination with a potassium supplement.