Quinine Overdose: Hypoglycemia Potentiated by Age and Alcohol

Abstract

Objective: To discuss a case of quinine toxicity and the impact that age and alcohol can have on its clinical presentation of life-threatening hypoglycemia. Case Summary: A 55-year-old white woman with a history of ethanol abuse developed quinine toxicity after accidentally consuming approximately 4 g of quinine. During her hospital stay, the patient developed life-threatening hypoglycemia, signs of cinchonism (tinnitus, lethargy), hypotension, and hypokalemia. She was treated successfully with intravenous fluids, dextrose, and potassium. Discussion: In reviewing the literature involving quinine toxicity, few cases have discussed the role quinine may play in the development of hypoglycemia. Quinine has been implicated as the cause of hypoglycemia in patients with malaria, but has less commonly been considered the cause in healthy patients. In this case report, the patient developed life-threatening hypoglycemia after the consumption of 4.6 g of quinine. Toxicity associated with quinine is usually detected at doses >4 g, but lethal doses have been reported to range between 2 and 8 g. The cause of this patient's sudden drop in glucose concentration was determined to be multifactorial and attributed to a combination of quinine, ethanol, and potential biologic aging of metabolic organs. Conclusions: Quinine can cause hypoglycemia; in this case it occurred at a toxic dose of 4.6 g. In older patients or patients with a significant history of alcohol abuse, this effect may be potentiated.