The supplement, developed in slow-release tablet form by Swiss pharmaceutical company Novartis and sold as Slow-K or Duro-K, is said to be particularly harmful when taken by pregnant women, as it puts their unborn babies at risk.
Speaking to NutraIngredients-Asia, a Novartis spokesman (who declined to be named) said: "We recently evaluated Slow-K / Duro-K by Novartis and found that selected batches contained levels of lead higher than the maximum specified by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), a new standard the Therapeutic Goods Administration (TGA) adopted on 1 December 2017."
He added that the company then informed and consulted with the Therapeutic Goods Administration, but the regulator gave no recommendation for the product to be recalled.
However, a letter has since been sent to alert all medical practitioners in Australia of the situation.
No total recall?
Presently, the TGA is allowing the supplement to remain available until current stock is depleted, but intends to have it gradually withdrawn.
The Novartis spokesman said, "We are working with the TGA to ensure a controlled withdrawal. We want to make sure there's enough time for appropriate alternatives to enter the market.
"Novartis has a significant market share of slow-release potassium chloride tablets in Australia, so a shortage of Slow-K / Duro-K may adversely affect certain patients."
In the meantime, the firm has advised doctors to look into and recommend alternative options for expectant mothers, women planning to conceive, or patients with moderate to severe hypokalaemia who have been prescribed more than two 600mg pills daily for a prolonged period.
A TGA representative told NutraIngredients-Asia: "Lead testing for 10 batches of Slow-K / Duro-K supplied in Australia returned reassuring results, (but) one of the batches returned a result that was higher than the permitted daily exposure of lead.
"However, this batch is no longer being distributed in Australia, and the risk to consumers is considered negligible. The TGA is working with Novartis to ensure the withdrawal of the Slow-K product to minimise the occurrence of a shortage."
In an official statement, Novartis said the product still has "an established favourable benefit / risk profile for the approved indications".
The statement also claimed that a review of cumulative safety data from clinical trials and post-marketing reports has not turned up any safety issues linked to exposure to lead from Slow-K / Duro-K.
She added at the moment, an Aspen Pharmacare-sponsored alternative called Span K was available on the Australian Register of Therapeutic Goods, and that the TGA has been collaborating with other sponsors to find an alternative supply of potassium chloride from overseas to ensure sufficient supply.