Two more people in the Netherlands have been hospitalised with nitazene poisoning after ingesting what they thought was the painkiller oxycodone, broadcaster NOS reported.

Doctors are also investigating if another two people who ended up in hospital with similar symptoms were exposed to nitazenes as well, NOS said.

Earlier this month, the Dutch health ministry and addiction clinic Trimbos issued a warning about the life-threatening fake version of the drug following the death of a 30-year-old man.

The fake oxycodone pills contain the potentially lethal chemical isotonitazepyne, a synthetic opioid which, according to some research, is 1,000 times more potent than morphine.

The man, who had had a minor operation on his nose, had reportedly bought the fake pill online and died after taking just half a tablet, his family told the AD.

“Ruben was a normal, healthy boy who liked sports. He was not an addict but a victim of malicious traders on the internet,” his brother told the paper.

Pharmaceutical patient care professor Marcel Bouvy said a very small amount of the substance can be lethal. “It is a chemical which copies the effect of oxycodone but it is effective in a much smaller dosage,” he said.

Oxycodone is a highly addictive painkiller used in the Netherlands by cancer patients and as part of palliative care. In 2023 some 489,000 people in the Netherlands were prescribed the drug.