Life‐threatening hypokalaemia and lactate accumulation after autointoxication with Stacker 2®, a ‘powerful slimming agent’

Abstract

In recent years the use of so-called fatburners such as Stacker® has gained widespread popularity in the USA. These dietary supplements contain substances such as Ephedra and caffeine.The drugs are supposed to stimulate athletic performance and reduce body weight [1]. Ephedra, also known as the Chinese ‘Ma Huang’, is a plant-derived natural source of the sympathicomimetic substance ephedrine. Caffeine (1,3,7-methylxanthine) is also a plantderived stimulant alkaloid, which can be obtained from tea leaves, coffee beans, cacao beans and cola nuts. Its pharmacological actions are diverse, but finally result in an increasing release of endogenous catecholamines and therefore augment the effect of Ephedra alkaloids. For years, Ephedra-containing food supplements were easily available over-the-counter herbal products in the USA and the Netherlands. When serious adverse events including stroke, heart attacks, cardiac arrhythmias, seizures and psychotic disorders were reported, the general sale of Ephedra-containing products was prohibited. However, Ephedra alkaloids can still easily be obtained through the internet or at gyms. Furthermore, an increase in the use of Ephedra-free fatburners, which are considered as ‘safe’ products, has been observed. In the following case report we describe a remarkable, potential lethal intoxication with Stacker 2®. A 22-year-old woman with no previous medical history was admitted to our emergency room because of attempted suicide. She claimed to have ingested approximately 50 tablets of Stacker 2® ephedra, which had previously been provided by her gym. According to the label on the bottle, its main constituents were Ephedra, cola nuts and white willow bark (NVE Pharmaceuticals®, Andover, NJ, USA).The patient reported not having taken any alcohol or other medication. Furthermore, she had not been exercising on the day of admission. On arrival, she complained of thirst, headache, abdominal pain, chest pain and she vomited several times. On examination, an anxious, hyperventilating and extremely agitated woman was observed with clammy peripheries. Vital signs included a temperature of 37.5 °C, blood pressure of 122/66 mmHg, a regular pulse of 110 bpm and a respiratory rate of 25/min. Her arterial saturation was measured at 99%. Pupils were bilaterally dilated and responsive. Apart from modest abdominal tenderness, physical examination revealed no other abnormalities. Laboratory results are shown in Table 1. Because of the strikingly low serum potassium concentration (1.6 mmol l-1), laboratory measurements were verified several times. Also remarkable was the elevated serum lactate (7.2 mmol l-1). Electrocardiography demonstrated sinustachycardia with ST-depression and U-waves in precordial leads V1–V3. Potassium chloride at a rate of 20 mmol h-1 was administered. Furthermore, sodium-potassium-phosphate was supplemented.The patient was transferred to the Intensive Care Unit for haemodynamic monitoring. Polyuria was observed with a diuresis of 250 ml h-1. The following day, the patient was less agitated, but still complained of nausea, vomiting and abdominal pain. Her respiratory rate still measured 22/min. Tachycardia had disappeared. The serum potassium concentration had increased from 1.6 to 3.8 mmol l-1. Serum lactate had decreased to 3.5 mmol l-1 (Table 1). The patient was transferred to the ward and discharged home 7 days after admittance. Subsequently, toxicological analysis for caffeine was performed by means of high-pressure liquid chromatography UV detection: platinum enhanced polar selectivity C18 column, particles; 3 mm, size 10 ¥ 4.6 cm; Alltech®, photodiode array detector (Waters®, Milford, MA, USA). The mobile phase consisted of a solution of water, phosphor acid, nonilamine (67%) and acetonitril (33%). Ephedrine British Journal of Clinical Pharmacology DOI:10.1111/j.1365-2125.2008.03279.x