Countdown shoppers will no longer be able to buy more than one packet of paracetamol from today onwards.
The supermarket says stores nationwide are limiting the sale of New Zealand's most popular medicine after a recent coroner's report.
David Robinson recommended a sales limit be introduced to help reduce the risk of an overdose after the death of a student in Dunedin.
Alannah Lee Spankie, 20, died from acute liver failure in June 2017 and Robinson ruled she did not intend to take her own life.
The University of Otago science student had taken a large amount of paracetamol before being found unresponsive three days later by her flatmates.
In his report, Robinson said a sales limit change in the United Kingdom reduced deaths related to the painkiller in England and Wales by 43 per cent.
Foodstuffs, which owns New World, Pak'nSave and Four Square, is consulting regulators before making a decision about sale limits.
Head of corporate affairs Antoinette Laird said the wellbeing of customers was paramount and they were aware of the coroner's recommendation.
Supermarkets in New Zealand are able to legally sell paracetamol without any limit on how many packets people can buy at once.
The painkiller has about three million prescriptions written and more than 50 million tablets used each year across New Zealand.
Countdown customers seeking long-term pain relief will now need to be prescribed larger quantities by a GP.
Jeremy Armes, Countdown's head pharmacist, said the supermarket had been looking at how it could sell paracetamol more safely and believed it was best the painkiller was sold in a pharmacy environment where a pharmacist could talk through the risks one-on-one.
"Paracetamol is an incredibly useful and effective medicine but, as with all medicines, it also needs to be respected and treated with care," Armes said.
"There is no doubt that mental health awareness, education and good medical support are going to make the biggest difference for Kiwis suffering with mental illness.
"However, there are also significant and sometimes tragic consequences of overdose, whether that is accidental or intentional."
Armes said anything the supermarket could do to reduce any risks surrounding paracetamol was a good thing.
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