Extreme QT Interval Prolongation Caused by Mad Honey Consumption

Risks for human health related to the presence of grayanotoxins in certain honey

The European Commission asked EFSA for a scientific opinion on the risks for human health of the presence of grayanotoxins (GTXs) in 'certain honey' from Ericaceae plants. The risk assessment included all structurally related grayananes occurring with GTXs in 'certain' honey. Oral exposure is associated with acute intoxication in humans. Acute symptoms affect the muscles, nervous and cardiovascular systems. These may lead to complete atrioventricular block, convulsions, mental confusion, agitation, syncope and respiratory depression. For acute effects, the CONTAM Panel derived a reference point (RP) of 15.3 μg/kg body weight for the sum of GTX I and III based on a BMDL₁₀ for reduced heart rate in rats. A similar relative potency was considered for GTX I. Without chronic toxicity studies, an RP for long-term effects could not be derived. There is evidence for genotoxicity in mice exposed to GTX III or honey containing GTX I and III, showing increased levels of chromosomal damage. The mechanism of genotoxicity is unknown. Without representative occurrence data for the sum of GTX I and III and consumption data from Ericaceae honey, acute dietary exposure was estimated based on selected concentrations for GTX I and III reflecting concentrations measured in 'certain' honeys. Applying a margin of exposure (MOE) approach, the estimated MOEs raised health concerns for acute toxicity. The Panel calculated the highest concentrations for GTX I and III below which no acute effects would be expected following 'certain honey' consumption. The Panel is 75% or more certain that the calculated highest concentration of 0.05 mg for the sum of GTX I and III per kg honey is protective for all age groups regarding acute intoxications. This value does not consider other grayananes in 'certain honey' and does not cover the identified genotoxicity.

Mad honey: uses, intoxicating/poisoning effects, diagnosis, and treatment

Honey has been used as a folk medicine since 2100 BC; however, mad honey is different from normal natural or commercially available honey as it is contaminated with grayanotoxins, which leads to intoxication/poisoning upon consumption. Grayanotoxin is generally found in Rhododendron genus (family: Ericaceae) and is extracted by bees from nectar and pollens of flowers. Mad honey has been commonly used as an aphrodisiac (sexual stimulant), in alternative therapy for gastrointestinal disorders (peptic ulcer disease, dyspepsia, and gastritis), and for hypertension for a long time. Grayanotoxin acts on sodium ion channels and muscarinic receptors, leading to cardiac disorders (hypotension and different rhythm disorders including bradycardia, bradydysrhythmias, atrial fibrillation, nodal rhythm, atrioventricular block, and complete atrioventricular block) and respiratory depression. Patients may also exhibit any one symptom out of or combination of dizziness, blurred vision, diplopia, nausea, vomiting, vertigo, headache, sweating/excessive perspiration, extremity paresthesia, impaired consciousness, convulsion, hypersalivation, ataxia, inability to stand, and general weakness. Mad honey intoxication is diagnosed with honey intake history before the appearance of the signs and symptoms (clinical presentation), and the treatment is symptomatic. Prompt treatment includes intravenous infusions of atropine sulfate and fluids (saline infusions or simultaneous infusion of saline with atropine sulfate) if the patient presents bradycardia and severe hypotension. In case of a complete atrioventricular block, a temporary pacemaker is employed. Except for a single case from Lanping County (Southwest China), the prognosis for mad honey intoxication is very good, and no fatalities have been reported in modern medical literature excluding a few in the 1800s. Although fatalities are very rare, mad honey ingestion may still lead to arrhythmias, which can be life-threatening and hard to recognize. This article provides a brief introduction to honey, mad honey and its uses, the effects of mad honey intoxication/poisoning, and its diagnosis, prognosis, and treatment.

Honey has been used as a folk medicine since 2100 BC; however, mad honey is different from normal natural or commercially available honey as it is contaminated with grayanotoxins, which leads to intoxication/poisoning upon consumption.

Mad honey intoxication: A systematic review on the 1199 cases

Mad honey, produced by honeybees from the nectars of Rhododendron genus (R. ponticum and R. luteum) flowers, is widely used in indigenous medicine, especially in the treatment of hypertension and sexual dysfunction. However, the consumption of this honey can result in intoxication soon after. The diagnosis of honey poisoning and a full understanding of its treatment is important for both effective and immediate treatment, and also for the prevention of unnecessary costs. Upon the evaluation of approximately 34 years of case reports between 1981 and 2014, it was found that the cases of poisoning were more frequently reported in males (75.17%) and between the ages 41 to 65. The most common complaints related to honey poisoning were dizziness, nausea, presyncope and the ECG findings were: sinus bradycardia (79.58%), complete atrioventricular block (45.83%), atrioventricular block (30.91%), ST-segment elevation (22.63%), and nodal rhythm (11.27%), As a result of the evaluation of 1199 cases, it was found that no deaths were reported. The patients were most frequently treated with 0.5 mg atropine (37.79%), 1 mg atropine (49.73%), salin (iv fluid) (65.35%), and generally the patients were discharged within 24 h after recovery.

Clinical characteristics and outcomes of patients with grayanotoxin poisoning after the ingestion of mad honey from Nepal

The aims of this study were to evaluate the clinical characteristics and outcomes of patients with grayanotoxin poisoning due to mad honey brought from Nepal. Medical records of patients with mad honey poisoning admitted to the emergency department between 1 January 2004 and 31 May 2012 were retrospectively reviewed. A total of 15 patients were included in this study. In all patients, mad honey was brought from the Himalayan region of Nepal. The mean age was 52.2 years, and 66.7 % were men. The mean amount of mad honey ingested was 47 cc, and the mean time from ingestion to onset of symptoms was 36 min. In all patients, initial vital signs showed hypotension and bradycardia. The initial electrocardiogram showed sinus bradycardia in eight patients, junctional bradycardia in four patients, complete atrioventricular block in two patients, and atrial fibrillation with slow ventricular response in one patient. Four patients were treated with intravenous normal saline solution only. Eleven patients were treated with intravenous normal saline solution and intravenous atropine sulfate in a dose ranging from 0.5 to 2.0 mg. In all patients, the blood pressure and pulse rate returned to normal limits within 24 h. There were no deaths. The clinical characteristics and outcome of grayanotoxin poisonings caused by the ingestion of mad honey from Nepal are similar with those of mad honey from the Black Sea region of Turkey.