Mulethi ("Stick Made Out of Root"): Two Cases of Store-Bought Licorice Toxicity

Introduction: There are many OTC supplements and foods with clinically significant adverse effects. One such compound is licorice, which can result in a syndrome similar to apparent mineralocorticoid excess when consumed in excess. The metabolism of licorice produces glycyrrhizic acid, which competitively inhibits 11β-hydroxysteroid dehydrogenase and allows for inappropriate cortisol binding to renal mineralocorticoid receptors. In this case series, we present two cases in which ingestion of store-bought licorice and its derivatives presents with classic and non-classical manifestations. Case Description: CASE 1: A 77M with neurocognitive disorder, HCV, HTN, recent poor intake and frailty presented with asymptomatic hypokalemia noted on outpatient labs. On admission, K was 2.5, Mg was 2.0, and HCO3 was 30. BP was 160/92, increased from previous. He received IV and PO repletions of KCl with limited improvement to 3.7 by day 3. He denied recent diuretic & laxative use, vomiting, or diarrhea, so his hypokalemia was initially thought to be due to poor intake. However, further questioning uncovered that he had been consuming bags of black licorice from multiple brands. Plasma aldosterone was <1.0. K was gradually repleted to 4.0 and he was discharged on day 5. CASE 2: A 75M with HTN, CAD s/p PCI presented with fatigue and dyspnea on exertion. In the ED, he was hypotensive, bradycardic, and hypokalemic with ST-depressions and U-waves on EKG. Careful history taking revealed that he had been taking licorice root extract for the past three weeks to treat fatigue. Serum K was 1.2, fractional excretion of K was 45%. Licorice was d/c'd, K was corrected, and bradycardia resolved, at which point he was found to be hypertensive. Discussion: Licorice and its derivatives are among many foods and OTC supplements with documented harmful effects in the appropriate setting. Other examples include tyramine in aged cheese (Hypertensive Emergency), St. John’s Wart (CYP-450 induction, Serotonin Syndrome), and gingko biloba (bleeding risk). Unfortunately, many potentially harmful products are easily purchased at grocery stores and pharmacies without warning labels – an issue compounded by an abundance of claims regarding potentially beneficial effects. Improved regulation and preventative measures to increase awareness about adverse effects could prevent potentially significant complications.