Pseudoaldosteronism induced by Yokukansan in an elderly Japanese type 2 diabetic patient with Alzheimer's disease

The number of patients with Alzheimer’s disease (AD), and/or behavioral and psychological symptoms of dementia (BPSD) has been markedly increasing all over the world, and has become a social and health problem. Furthermore, it has been recently established that the diabetic condition is a major risk factor for the development of dementia. Second-generation antipsychotics have been used, but some cases are refractory. Yokukansan is a licorice-containing Chinese medicine, and has been very often used for the treatment of such disease. A previous report showed that Yokukansan exerts beneficial effects and can be used very safely. It is known that a large amount of licorice could induce pseudoaldosteronism, but Yokukansan contains only a small amount of licorice. Therefore, it has been thought that the use of Yokukansan does not lead to the onset of pseudoaldosteronism. However, here we report a case of pseudaldosteronism that developed after starting Yokukansan in an elderly Japanese diabetic patient with AD and BPSD. In February 2013, a 77-year-old Japanese man with type 2 diabetes was admitted to the Kawasaki Medical School, Kurashiki, Japan, because of hypokalemia and weight gain. He had been taking Yokukansan for 5 months (7.5 g/day containing 1.5 g of licorice). He frequently felt general fatigue, and his bodyweight was increased by 7 kg. On admission, his bodyweight was 64.3 kg and height 160.5 cm. He did not have vomiting or diarrhea and did not use any diuretics. Physical examination revealed mild systolic hypertension. Marked pretibial pitting edema was observed in the bilateral lower extremities. Table 1 shows the laboratory findings on admission. Serum potassium was 3.0 mEq/L with mild renal dysfunction. The low-renin and low-aldosterone state was observed with concomitant metabolic alkalosis. In addition, the transtubular potassium gra-