Acute Sophora alkaloid poisoning in Hong Kong

Sophora alkaloids, including matrine, oxymatrine, and sophoridine, are quinolizidines found in plants used in traditional Chinese medicine such as Sophora flavescens and Sophora tonkinensis. Reports on acute Sophora alkaloid poisoning in humans outside of mainland China are lacking. This study aimed to characterize the clinical presentations, management, and outcomes of acute poisoning involving Sophora alkaloids in Hong Kong. We conducted a retrospective study of patients who were reported to the Hong Kong Poison Control Centre from all public emergency departments (EDs) in Hong Kong for acute poisoning involving Sophora alkaloids. Exposure was confirmed by laboratories, and data were collected between July 1, 2008 and June 30, 2021. We also analyzed patient demographics, clinical, management, and outcome characteristics. Among the 83 cases analyzed, S. flavescens was the major source (77.1%) of Sophora alkaloids and excessive dose was common (39.0%). Most patients (90.4%) had minor effects. Common clinical presentations were dizziness (83.1%), vomiting (72.3%), and palpitations (32.5%). No acute liver or kidney injuries or adverse skin reactions were observed. Treatment was primarily supportive and no patients underwent gastrointestinal decontamination, organ support treatment, or renal replacement therapy. Most patients (74.7%) were observed in the ED and only one required close monitoring in a cardiac care unit for prolonged QT interval after concurrent ciprofloxacin use. In contrast to the intravenous administration of S. flavescens, no adverse skin reactions were seen after oral consumption. Hepatoxicity, reported in in vitro and animal studies, and isolated human case reports, was not observed. In conclusion, excessive dose of S. flavescens is a common cause of acute Sophora alkaloid poisoning. Although most patients had mild symptoms, discrepancies in clinical presentations resulting from different formulations and varied experimental/clinical conditions call for further studies to evaluate the real-world risks of skin reactions and hepatoxicity of Sophora alkaloids.