Physician Beware: Severe Cyanide Toxicity from Amygdalin Tablets Ingestion

August 2017
Tam Dang, Cham Nguyen, and Phu N. Tran

Abstract

Despite the risk of cyanide toxicity and lack of efficacy, amygdalin is still used as alternative cancer treatment. Due to the highly lethal nature of cyanide toxicity, many patients die before getting medical care. Herein, we describe the case of a 73-year-old female with metastatic pancreatic cancer who developed cyanide toxicity from taking amygdalin. Detailed history and physical examination prompted rapid clinical recognition and treatment with hydroxocobalamin, leading to resolution of her cyanide toxicity. Rapid clinical diagnosis and treatment of cyanide toxicity can rapidly improve patients' clinical outcome and survival. Inquiries for any forms of ingestion should be attempted in patients with clinical signs and symptoms suggestive of poisoning.

1. Introduction

Amygdalin (also known as Laetrile or vitamin B17) is a poisonous cyanogenic glycoside substance found naturally in many plants, including raw nuts such as bitter almonds and the pips of many fruits (particularly apricot pips or kernels). Amygdalin was isolated by French chemists in 1830 and it was first used as a treatment for cancer in Russia in 1845. In the United States, amygdalin was used in the 1920s. In the 1980s, The National Cancer Institute sponsored phase 1-2 clinical trials but found no evidence to support the clinical benefits of amygdalin in cancer treatment [1]. Furthermore, amygdalin was associated with cyanide poisoning, especially from oral ingestion [1]. As a result, the Food Drug Administration (FDA) banned the sale of amygdalin as a medicinal product. However, it remains available in the market and has been promoted as an alternative cancer treatment.