Pseudoaldosteronism due to the concurrent use of two herbal medicines containing glycyrrhizin: interaction of glycyrrhizin with angiotensin-converting enzyme inhibitor.

A 77-year-old man with a history of hypertension and hyperuricemia was admitted to our hospital complaining of limb weakness, persistent constipation, and worsening hypertension. He had been taking a Chinese herbal remedy for allergic rhinitis for the past 10 years, together with an angiotensin-converting enzyme inhibitor (ACE-I; enalapril, 20 mg daily). After the dosage of enalapril had been reduced to 10 mg daily about 1(1/2) years before the current admission, he had developed persistent constipation. Therefore, he had started taking another traditional Chinese herbal remedy, a laxative, for the constipation, about 4 months prior to this hospitalization. Laboratory data on admission demonstrated marked metabolic alkalosis with severe hypokalemia associated with urinary wasting of potassium and chloride. A diagnosis of pseudoaldosteronism was made based upon his past history of exposure to various traditional Chinese medicines containing glycyrrhizin. Discontinuation of the Chinese remedies and supplementation of potassium successfully normalized the electrolyte imbalance and relieved all symptoms within a short time. The present case describes the occurrence of pseudoaldosteronism induced by a patient taking two traditional Chinese herbs, both containing glycyrrhizin, resulting in an overdose of this causative chemical agent. The development of pseudoaldosteronism appeared to be of particular interest with regard to the interaction of the renin-angiotensin-aldosterone (RAA) system with glycyrrhizin, in which an ACE-I retarded the development of pseudoaldosteronism.