Heath Canada warned Friday that some EpiPen and EpiPen Jr auto-injector devices may not easily slide out of their carrier tube — a problem the agency says could delay or prevent emergency treatment, possibly leading to patient disability or death.

The advisory comes after Pfizer Canada notified the agency that, in a small number of devices, EpiPens' labels have been improperly applied, causing auto-injectors to become stuck to the inside of their carrier tubes and making it difficult or impossible for them to be administered.

Products affected have expiry dates between April 2018 and October 2019.

According to the advisory, Pfizer is not recalling the auto-injectors "as the risk can be mitigated easily by pharmacists and patients by checking devices before an emergency situation arises to make sure they slide easily out of their carrier tube."

EpiPen and EpiPen Jr are used to deliver an emergency dose of adrenaline to patients facing serious allergic reactions.

According to the advisory, Pfizer is not aware of any reports of product malfunctions related to this issue in Canada.