Two medical researchers are calling for tighter controls on paracetamol sales after their hospital audit found it is the drug of choice for self-harm, especially among teenage girls.
Paracetamol, sold in a variety of brands including Panadol, is available on a doctor's prescription, from pharmacies and from supermarkets, dairies and other shops.
It is generally a safe form of pain relief, but taking too much can cause liver damage and death.
Nadia Freeman and Paul Quigley found it was the most common cause of medication poisonings in patients at Wellington Hospital's emergency department from 2007 to 2012, accounting for 23 per cent of cases.
The sleeping tablet Zopiclone was second, on 9 per cent, the researchers report in today's New Zealand Medical Journal.
In 2013, of the 879 cases of overdose at the ED, paracetamol was the main drug in 172 (20 per cent). Eighty-six per cent of the paracetamol overdoses were cases of deliberate self-harm and attempted suicide.
Of those who took paracetamol to harm themselves, 80 per cent were female and half were under age 20.
Nationally, the researchers found, there were 1712 hospital admissions in 2012 for paracetamol poisoning. They estimate the paracetamol cases cost the health system more than $2.9 million.
"New Zealand does not restrict the amount of paracetamol that can be purchased in pharmacies, and has set a limit of 10g [20 tablets] per packet for all other outlet types, with no limit on the number of packets that may be purchased," the researchers say.
They recommend following Britain, where general sales are limited to 16 tablets, with a limit at pharmacies of 32, with discretion to sell up to 100 at pharmacies, although they note the conflicting evidence on the effects of the 1998 British legislation.
Several studies found no changes in paracetamol-related suicides or referrals to transplant units in Scotland, but others found a 20 per cent reduction in paracetamol-related overdoses, a 22 per cent reduction in deaths and a 30 per cent reduction in liver-unit admissions.
The Freeman-Quigley paper also urges authorities to look at an age limit for buying paracetamol, because of the high proportion of overdoses among those under 20.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• The Word
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention
If it is an emergency and you feel like you or someone else is at risk, call 111.