Paracetamol is cheap and readily available – you can pick it up at the supermarket along with your toothpaste and deodorant. But as with any drug, the painkiller can be dangerous if you take more than the correct dose. In this country, and Australia, it is the No 1 pharmaceutical that Poisons Information Centres receive calls about, and most of those calls concern young patients.
Legally, supermarkets are able to sell paracetamol without any limit on the number of packs a person can buy. However, supermarket chain Countdown has now voluntarily limited sales to one pack per customer following a recommendation by the coroner who examined the overdose death of Dunedin student Alannah Lee Spankie.
Spankie took a large amount of paracetamol while in an emotionally upset state, and later died of liver poisoning. Coroner David Robinson found she didn't intend to take her own life, and called for a sales limit to help prevent more accidental deaths.
Harmful use of painkillers is an increasingly common problem, says Rose Cairns, a poisons specialist at the University of Sydney. A study she published last year found that in Australia, the annual number of paracetamol poisoning cases had increased by 44% over a 10-year period, and liver injury doubled over that time.
"We were particularly concerned about modified-release paracetamol, which is harder to treat in overdose and has poorer outcomes," she says.
Reducing access has been shown in other countries to be effective. A law change in the UK, limiting paracetamol pack sizes, resulted in a 43% reduction in deaths in England and Wales.
"What many people don't realise is that self-poisoning is often impulsive," says Cairns. "If you're having an acute crisis, access to dangerous amounts of medicine is risky."
Most New Zealand households have a stock of paracetamol. A recent University of Otago study found that a third of us have 30g or more (60 pills) in our homes.
Cairns says it is surprisingly easy to take a harmful amount unintentionally.
"Typically, it's people who are in pain and they'll take more than the packet says, not realising it could be a problem. If you do that for several days in a row, it can be very dangerous, and fairly low doses can cause liver toxicity.
"There are warnings on the packet, but people don't always read them properly. And they might be using another product, such as a cold and flu medicine, also containing paracetamol and not realise they are doubling up."
Taken at the recommended dose, paracetamol is metabolised by the liver and detoxified. But in large amounts, the painkiller overwhelms the body's ability to process it safely. This leads to a build-up of a reactive metabolite, a toxic byproduct that binds to the liver cells and causes damage.
"In severe cases you get really bad liver failure that requires a transplant or the person will die," says Cairns. "It's a slow and devastating process. People take an overdose and may regret what they've done, but they feel fine, so think they don't need help.
"Typically, symptoms don't develop for at least eight to 12 hours and the peak of the liver damage can be a couple of days after the overdose."
Modified-release tablets are especially problematic, and in New Zealand these are now pharmacist-only drugs. In European Union countries they are no longer available.
Cairns welcomes Countdown's decision to limit sales, but believes more needs to be done to reduce harm in both Australia and New Zealand.
"The majority of paracetamol use is appropriate and we shouldn't lose sight of that. It's always a balancing act of not restricting it for people who actually need it and also keeping vulnerable people safe," she says.
In supermarkets, you can buy a 20-tablet pack of paracetamol. Reducing that size would be a positive move, in her opinion. "It is still a problematic dose. Smaller packs would be sufficient for treating an acute condition, and if someone is in chronic pain and needing more, then they should be speaking to a pharmacist or doctor about it anyway, because there may be something better for them."
Poisoning with paracetamol is happening in all age groups, says Cairns. "It's one of the most commonly used medicines in the world, so it's not surprising that there are a lot of poisoning calls about it, but I think people may be unaware of the risks."
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
OR IF YOU NEED TO TALK TO SOMEONE ELSE:
• 0800 543 354 (0800 LIFELINE) or free text 4357 (HELP) (available 24/7)
• YOUTHLINE: 0800 376 633
• NEED TO TALK? Free call or text 1737 (available 24/7)
• KIDSLINE: 0800 543 754 (available 24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• DEPRESSION HELPLINE: 0800 111 757 or TEXT 4202