There are calls for warning labels to be added to cream of tartar, a staple in many kitchens, after the third recorded case of life-threatening cardiac toxicity linked to the pantry item in just over a decade.
In a case recently reported to The Medical Journal of Australia [link here], clinicians, including Dr Daniel Ng at Barwon Health in Geelong, describe a young woman who suffered two cardiac arrests after ingesting a homemade “cleansing” remedy for chronic constipation made with large amounts of cream of tartar, or potassium bitartrate.
“This is a common household item that presents an under-recognised danger,” the report states. “It is possible that the public perceive this pantry product as a safe alternative to pharmaceutical treatments, not realising that the high potassium content can be potentially fatal.”
Used mainly as a stabilising agent in baking, cream of tartar also has stool-softening properties when combined with bicarbonate in over-the-counter suppositories. But its extremely high potassium content makes it dangerous when consumed in large doses. Food Standards Australia New Zealand (FSANZ) data shows that 100 grams of potassium bitartrate contains 16.5 grams of potassium – making it easy to exceed recommended daily limits of 2.8-3.8g with just a few tablespoons.
The patient in the most recent case – a 45kg adult with a medical history of chronic constipation as well as schizophrenia without psychosis – consumed approximately 27.4 grams of potassium, equating to 15.56 mmol/kg – a quantity that exceeded daily potassium intake recommendations up to tenfold.
Just six hours after ingesting the home remedy, the patient developed symptoms of malaise, lower limb weakness, abdominal pain and a feeling of impending doom. By the time she arrived to emergency, the patient was already in cardiac arrest. Treating doctors performed 19 minutes of cardiopulmonary resuscitation (CPR), including four defibrillator shocks of 200 J for ventricular fibrillation (Box 1) and pulseless ventricular tachycardia before return of spontaneous circulation.
Despite early interventions, including calcium gluconate, insulin-dextrose, and sodium bicarbonate, the patient suffered a second cardiac arrest hours later due to rebound hyperkalaemia, likely the result of potassium shifting back out of cells and into circulation, the authors suggest.
They say additional measures may have helped mitigate the rebound, including intravenous furosemide to promote potassium excretion, earlier use of sodium polystyrene sulfonate, and possibly dialysis.
The source of influence behind the ingestion remains unclear, though the patient’s family and friends mentioned an unidentified YouTube video, highlighting the ongoing role of online misinformation in unsafe self-treatment practices.
The case follows two others involving healthy young men who developed symptomatic hyperkalaemia and ECG abnormalities after ingesting large amounts of cream of tartar for similar bowel cleansing purposes.
In all three cases, patients appeared to have self-administered the compound based on misinformation, with little understanding of the compound’s high potassium content.
The latest incident has been reported to FSANZ, with the clinicians involved calling for mandatory warning labels to alert consumers to the potential for fatal electrolyte disturbance.
“Warning labels should be incorporated in packaging to avoid recurrence,” they wrote. “Understanding of the anticipated course of potassium bitartrate ingestions will benefit clinicians to initiate urgent patient transfer and more targeted treatment.”