Review of Case Reports on Adverse Events Related to Pre-workout Supplements Containing Synephrine.

The use of pre-workout supplements has become increasingly popular, including the use of supplements containing synephrine. Synephrine might stimulate weight loss and improve sports performance by its proposed adrenergic properties. However, with its increasing popularity, numerous cases of adverse events related to synephrine use have been reported. This study provides a comprehensive overview and analysis of current case reports related to the supplemental use of synephrine. The scientific literature on cases of adverse events related to synephrine intake was collected through August 2021 using Pubmed and Google Scholar and subsequently reviewed and analysed. We obtained 30 case reports describing a total of 35 patients who suffered from medical complaints following use of synephrine-containing supplements. The patients most often presented with chest pain, palpitations, syncope and dizziness. Commonly raised diagnoses were ischaemic heart disease, cardiac arrhythmias and cerebrovascular disease. Five patients were left disabled or remained on medication at last follow-up. We here show an association between the use of pre-workout supplements containing synephrine and adverse events, mainly related to the cardiovascular system. However, we cannot exclude a role of possible confounding factors such as caffeine. Thus, the use of pre-workout supplements containing synephrine may lead to serious adverse health events, and therefore, caution is needed.

Barium toxicity and the role of the potassium inward rectifier current.

INTRODUCTION: Barium is a stable divalent earth metal and highly toxic upon acute and chronic exposure. Barium is present in many products and involved in a number of industrial processes. Barium targets the potassium inward rectifier channels (IRCs) of the KCNJx gene family. Extracellular barium enters and strongly binds the potassium selectivity filter region resulting in blockade of the potassium conducting pore. IRCs are involved in numerous physiological processes of the human body and the most barium sensitive IRCs are highly expressed in all muscle types. OBJECTIVE: Our purpose was correlate to the clinical outcome of acute barium poisoning in man to current knowledge on IRC function. METHODOLOGY: The primary literature search was performed using Medline, Scopus and Google Scholar using search terms "barium AND poisoning"; "barium AND intoxication"; "barium AND case report" and retrieved publications from 1945 through 2012. Additional case reports were retrieved based on the reference lists of the primary hits. Duplicate publications, or publications presenting identical cases were omitted. A total of 39 case reports on acute barium poisoning containing 226 human subjects were identified for review. RESULTS: BaCO3 was the most frequent source and food the most frequent mode of poisoning. Patients suffered from gastrointestinal (vomiting, diarrhea), cardiovascular (arrhythmias, hypertension), neuromuscular (abnormal reflexes, paralysis), respiratory (respiratory arrest/failure) and metabolic (hypokalemia) symptoms. Severe hypokalemia (< 2.5 mM) was observed from barium serum concentrations greater than or equal to 0.0025 mM. Review of the ECG outcomes demonstrated ventricular extrasystoles, ST changes and profound U-waves to be associated strongly with poisoning. Most common treatment modalities were gastric lavage, oral sulfates, potassium i.v. and cardiorespiratory support. 27 patients (12%) died from barium poisoning. CONCLUSIONS: Barium is a potent, non-specific inhibitor of the potassium IRC current and affects all types of muscle at micromolar concentrations. Gastrointestinal symptoms frequently occur early in the course of barium poisoning. Hypokalemia resulting from an intracellular shift of potassium and the direct effect of barium at the potassium channels explain the cardiac arrhythmias and muscle weakness which commonly occur in barium poisoning. Treatment of barium poisoning is mainly supportive. Orally administered sulfate salts to form insoluble barium sulfate in the intestinal tract and potassium supplementation have potential but unproven benefit.