Heroin found in cocaine and ‘ice’, and snorting a line can be lethal

Authorities in New South Wales and Victoria have been warning the public about worrying cases of heroin overdoses after people thought they had taken cocaine or methamphetamine.

We know the issue is also relevant to other parts of Australia. And it’s particularly concerning because heroin can cause life-threatening opioid overdoses, particularly in people inexperienced with heroin who snort it.

Our new research sheds more light on what happens to people who accidentally took heroin thinking it was something else.

What we did and what we found

We are part of a NSW Health program that helps to find and quickly respond to concerning illicit and recreational drug poisonings and trends. The program is a collaboration between many government health services, including hospitals, the NSW Poisons Information Centre and labs.

We searched our database and found 34 cases of opioid overdoses after using what people thought to be a stimulant drug between January 2022 and June 2024. A total of 19 people thought they were taking cocaine and 15 methamphetamine.

Most of these 34 people had a severe opioid overdose requiring treatment by paramedics and in hospital. Sadly, two people died.

Heroin was the opioid in all cases where we specifically tested for it, and we suspect all the cases.

Cases occurred across NSW but most cases (68%) were in Sydney. In the last eight months of our study we identified multiple cases each month which may indicate these cases are becoming more common.

In the United States, drugs like cocaine and methamphetamine are sometimes mixed with the potent opioid drug fentanyl. This unintentional use of opioids is causing many deaths in the US. But we didn’t find any evidence that fentanyl was the cause of the overdoses we examined.

What happens when you take heroin by accident?

Cocaine and methamphetamine are stimulant drugs. These are drugs that make a person feel more energetic and confident, and their pupils become larger.

They have the opposite effect to heroin, which is an opioid and sedative. Heroin and other opioids make a person feel relaxed and often drowsy, with smaller pupils.

When overdosing, opioids cause loss of consciousness and a person’s breathing slows or even stops, which is life-threatening. Severe opioid overdose without prompt treatment is lethal.

If you expect to be taking cocaine or methamphetamine, but it is actually heroin, or has some heroin in it, you will very likely overdose. This is particularly true if you don’t usually take opioids, or if you use it for the first time. People can overdose from as little as snorting a line.

Why is this happening?

Sometimes people get a different drug than they wanted. This can happen because the drug is mixed with something else or swapped.

This can happen for many reasons, including during manufacturing and distribution. It can happen intentionally or unintentionally by the dealer or people using the drug.

One major reason is that you sometimes can’t tell heroin apart from cocaine or methamphetamine just by looking at them. So if drugs are mixed or swapped, you can’t always tell until you take them.

What can we do about it?

Opioid deaths are preventable. Government and community groups are working together to respond to the problem, either via issuing drug alerts or by educating their members.

But people who take illicit or recreational drugs can reduce their risk by avoiding using drugs alone, and by making sure one person in their group is able to get help if needed.

Unexpected sleepiness is a reason to seek help, not to simply rest. Start CPR if someone is not responsive and call 000.