An unusual presentation of chronic cyanide toxicity from self-prescribed apricot kernel extract

Abstract

Hypoxia under general anaesthesia is a potentially life-threatening condition. A seemingly well 67-year-old man appeared hypoxic with peripheral pulse oximetric measurement during routine anaesthesia. Postoperatively, the patient admitted to daily self-prescription of apricot kernel extract for a period of 5 years. Apricot kernel is a commonly taken extract used for a range of ailments, and is associated with cyanide toxicity, which was confirmed through blood analysis. Our explanation for the hypoxic measurement was the presence of free cyanide interfering with functioning of the peripheral pulse oximeter. On cessation of the apricot kernel extract, peripheral oxygen saturations returned to normal. Cardiac and respiratory causes together with rare haemoglobinopathies were excluded. This case illustrates how chronic dosing of complementary medicines can result in harmful toxicities, which may carry potential for serious consequences and how these chronic toxicities may present to physicians in atypical ways.

Acceptability of pharmacist-led interventions to resolve drug-related problems in patients with chronic myeloid leukaemia

“…Patients were also discouraged from using herbal remedies with potential safety issues, such as apricot seeds with reported cyanide toxicity. 29 A previous study has suggested that a majority of patients (60%) with haematological cancer in Malaysia did not voluntarily inform their physicians about their CAMs usage. 30 Therefore, pharmacists play an essential role in reviewing the use of CAMs by CML patients and monitoring these patients for potential drug-vitamin-herb interactions.…”

Toxicity of herbal medications suggested as treatment for COVID‐19: A narrative review

“…[35][36][37] Apricot seeds toxicity stems from the chemical compound amygdalin, 35,37,38 which is naturally occurring in many plants, but most notably in the seeds of apricots, bitter almonds, plums, apples, and peaches. 35,37,38 Amygdalin is often sold under the name "Vitamin B17," despite not being a vitamin, and a semisynthetic form known as laetrile 36,37 was used as an alternative cancer therapy before being banned by the FDA in 1978. 36 Amygdalin is toxic because when ingested, it is readily metabolized by the enzyme beta-glucosidase to hydrocyanic acid, or cyanide.…”

“…35,37,38 Later signs include nausea, vomiting, arrythmias, coma, pulmonary edema, and renal failure. 35,37,38 The diagnosis is often made clinically, but a profound lactic acidosis is often seen on laboratory values and may aid in making the diagnosis. 37,38 Serum cyanide levels can be drawn but typically will not result in sufficient time to aid in treatment of the patient.…”

Evaluation of the health risks related to the presence of cyanogenic glycosides in foods other than raw apricot kernels

“…It was then discovered that the patient self‐administered three 2 g tablets of Novodalin (a proprietary amygdalin preparation) and had two teaspoons of home‐made apricot kernel extract per day. Analysis of Novodalin showed cyanide levels of 220 mg/kg and the homemade apricot kernel extract 1,600 mg/kg of cyanide, meaning that the patient ingested daily approximately 17.32 mg of oral cyanide (Konstantatos et al., ). While the high blood cyanide level is explained by the ‘medication’ of the patient, it should be noted that cyanide intoxication does not lead to blood hypoxia.…”