Licorice of 'shakuyaku kanzou tou' induced pseudoaldosteronism

We report a case of pseudoaldosteronism induced by licorice in a kampo medication 'Shakuyaku Kanzou Tou' that was diagnosed after relief of urinary retention due to benign prostatic hypertrophy (BPH). A-71-year-old man was admitted to our hospital due to urinary retention. At admission, he had hypertension and leg edema, but serum potassium was in the normal range. One day after admission, hypokalemia was recognized. He was taking "Shakuyaku Kanzou Tou", a Chinese medicine that contains glycyrrhizin. So we suspected pseudoaldosteronism and had him stop taking it. Computed tomography did not reveal any adrenal tumor. Plasma rennin activity and aldosterone level were suppressed. Gradually, hypertension and leg edema improved and serum potassium became within the normal range. We diagnosed the case as pseudoaldosteronism induced by licorice of 'Shakuyaku Kanzou Tou'. Since we suspected BPH to be the cause of urinary retention, we performed transurethral resection of prostate. After surgery, he was able to void smoothly.