A recent Freedom of Information request has revealed that a large quantity of an addictive and potentially lethal painkiller disappeared from a hospital in Victoria.

The Vancouver Island Health Authority said the liquid product that went missing from Royal Jubilee Hospital in 2015 was a mixture of fentanyl and another medication surgery patients receive to deal with pain.

The health authority admits the incident was one of the largest losses of fentanyl in its history.

"It's a meaningful amount of drug that was in these two products, and as a result there is concern as to where it did go, and the impact it might have based on where it went," said Richard Jones, Island Health's director of pharmacy services.

Few details are being released about the drugs' disappearance; the loss was only revealed when freelance journalist Stanley Tromp made an FOI request.

Island Health reported the loss to Health Canada as required — but didn't disclose it publicly. Jones said it would be up to Health Canada to disclose the content of the report.

Some drug losses are a reality for any healthcare facility, Jones said, and the missing quantity of fentanyl is a small fraction of the hundreds of thousands of doses the health authority uses each year.

He said Island Health is working to re-educate staff on the security of narcotics.

The health authority is not commenting on whether police are involved. Jones wouldn't speculate on whether the missing drugs ended up on the street.

With files from Megan Thomas