EpiPen injectors used to treat life-threatening allergic reactions are currently running short, and EpiPen Jr. products may soon do the same, Health Canada said on Thursday.

Health Canada said Pfizer Canada had advised the agency of the short supplies.

The auto-injector is a handheld device that treats life-threatening allergic reactions by automatically injecting a dose of epinephrine.

"A shortage does not necessarily mean that there is no supply available in pharmacies. At this time, the company has indicated that limited inventory of both products remains available and is being carefully managed nationally," the regulator said.

There are currently no alternative auto-injectors available in Canada.

Pfizer said the current supply constraints of its 0.3 mg and 0.15 mg products are due to delays at the manufacturing facility.

"It's related to manufacturing delays as well as limited third-party quantities of a component for the product," Christina Antoniou, Pfizer Canada corporate affairs manager said. "Unfortunately, I don't have a lot of detail on what that component is."

It is not unusual for EpiPen to be on back order for limited periods of time, Antoniou said.

Company offers help to find EpiPens

If the supply is limited at a pharmacy then Antoniou encouraged consumers to visit another pharmacy or to contact Pfizer at 1-877-374-7361 for up-to-date information about the shortage, estimated re-supply dates, and to secure the product.

Health Canada reminded patients and caregivers that EpiPen products expire on the last day of the month indicated on the product packaging. That means if a product is marked as expiring in January, it remains valid and not expired until Jan. 31.

Generally, people are advised to have more than one auto-injector with different expiry dates.

"However, in this shortage situation, if you are experiencing an anaphylactic reaction and have only an expired auto-injector, use the expired product and immediately contact 911. Regardless of whether the product is expired, you should get to the nearest hospital as soon as possible following the administration of the product, as instructed in the product labelling."

The EpiPen Jr. (0.15 mg) (DIN 00578657) is expected to be in shortage as of Friday, the company said.

The company reported that the shortage for both products is anticipated to be resolved on May 31, Health Canada said in an email. Pfizer later updated the information in an email to CBC News saying it cannot say exactly when the situation will be resolved.

Patients with questions or concerns about the shortage may also wish to speak to their health professional.

Dr. Supriya Sharma, Health Canada's chief medical adviser, said many factors aligned to create this situation.

"Emergency situation, one producer, no other global supply. So it is unusual," Sharma said in an interview. "Having said that, we are seeing globally more and more consolidation on the manufacturing side."

The announcement follows a series of shortages in EpiPens.

In 2017, the U.S. Food and Drug Administration sent a warning letter to Pfizer's facility, Meridian Medical Technologies, regarding complaints of its EpiPen products failing to operate during life-threatening emergencies.

The product is manufactured at Meridian but the current shortage does not relate to the U.S. regulator's warning letter, Antoniou said.