Kate Russell thought getting an iron infusion would help alleviate her fatigue, but instead she says the treatment led to a condition that landed her in an induced coma.
The 46-year-old said she was not warned about the potential risks and the 12 months since her admission to Toowoomba Hospital's intensive care unit (ICU) had been "devastating".
Ms Russell said she was diagnosed with severe hypophosphataemia, where phosphate levels in the blood become dangerously low, which can occur following an iron infusion.
"[I had] countless specialist appointments and medications, as well as using up all my personal leave and having to give up parts of my role [as a teacher],"
Ms Russell said.
"It's taken a huge financial toll on my family."
Kate Russell says she was active before getting an iron infusion. (Supplied: Kate Russell)
She said the only risk associated with having an iron infusion she was informed about was iron staining on her arm where the intravenous needle was inserted.
But Ms Russell said she started experiencing muscle weakness and heart palpitations after her treatment in October last year, and she continued to deteriorate for a month before she collapsed in a doctor's surgery and was rushed to hospital.
"I just could not continue to breathe, so they decided that they needed to take over my breathing and intubate me,"
she said.
She said when the cause of her illness was identified, she was given phosphate replacement therapy.
Iron infusion risk becoming more common
Women of reproductive age are getting iron infusions at an increasingly high rate. (ABC: Emily Bryan)
Medical experts say hypophosphataemia is a complication that can occur with the use of ferric carboxymaltose, an intravenous iron preparation commonly administered in Australia.
Recent data shows it is becoming more common as the use of iron infusions surges across Australia, particularly among women of reproductive age.
There were 46 reports of hypophosphataemia associated with ferric carboxymaltose in 2025, compared with 17 cases in 2020 according to the Therapeutic Goods Administration (TGA).
Bond University assistant professor and general practitioner Kieran Le Plastrier said several patients had presented to his practice feeling "generally unwell" after receiving an iron infusion this year and blood tests had shown they all had low phosphate.
Hypophosphataemia is becoming more common as the use of iron infusions rises. (Supplied: Queensland Health)
"They felt really, really terrible at a time when they're expecting to feel really great because we've done the iron infusion,"
he said.
Dr Le Plastrier said ferric carboxymaltose caused hypophosphataemia by preventing the breakdown of a hormone, which in turn signalled the kidneys to excrete more phosphate than usual.
"All versions of infusions can do it, but this particular product has a high rate because it blocks the conversion of certain cofactors in the gut and in the blood from being able to recycle and absorb phosphate," he said.
"Phosphate turns over every day; we excrete it in our kidneys and in our stool and this product can actually cause that to increase significantly."
He said patients experiencing low phosphate levels were treated with an oral replacement and usually returned to regular health within a few months in mild cases.
Kieran Le Plastrier says iron infusions can cause the kidneys to waste phosphate. (ABC Gold Coast: Danielle Mahe)
US strengthens warnings
Last month, the US Food and Drug Administration (FDA) brought in its strongest safety warning, a boxed warning, for ferric carboxymaltose due to the risks of hypophosphataemia.
The Therapeutic Goods Administration (TGA) said it was "aware of and currently evaluating" the move in the United States, but did not say whether Australia would adopt the same warning.
The organisation said it routinely monitored safety information and added that action taken by overseas regulators did not automatically result in the same action in Australia.
Royal Australian College of General Practitioners (RACGP) co-deputy chair Aadhil Aziz said Australian regulators should consider following the US to ensure patients and healthcare professionals were better informed about the potential risk.
"Having a warning doesn't mean that you don't do this," Dr Aziz said.
"It just means that you're paying more attention to the phosphate, and I don't think that's a bad thing."
He said patients should discuss dietary changes or oral iron tablets with their regular doctor before opting for an iron infusion.
For patients who required intravenous iron, he said checking phosphate levels before treatment could also help identify potential risk factors.
"We want our Australian patients to be safe and by focusing on safety first, making sure that this doesn't happen and what can be prevented is prevented,"
Dr Aziz said.
Kate Russell urges others to be aware of symptoms. (Supplied: Kate Russell)
Meanwhile, Ms Russell said it had taken her almost a year to recover, and she had only recently returned to work full-time as a physical education teacher.
She urged anyone thinking about getting iron infusions to do their research before getting the treatment.
"Look out for these symptoms post-iron infusion. If you experience it, go straight back to your GP,"
she said.
"I don't think anyone should have to experience this."