Health Canada and Pfizer Canada are warning Canadians of a shortage of an important life-saving device. 

Pfizer Canada is the maker of the popular EpiPen and Health Canada says the company has told them they expect to be in short supply of the product through the month of August.

The drug company expects the EpiPen 0.3 mg format to be in very limited supply in pharmacies.

Health Canada says, "This means that while some pharmacies may currently have some inventory on-hand, it will likely be depleted in the coming days or weeks. Pfizer Canada does not expect to be able to provide new supply until the end of August."

Pfizer says that they will be able to continue to supply the EpiPen Jr (0.15 mg), but that supply is also limited and "is being carefully managed at a national level."

EpiPens are auto-injectors of epinephrine, which counteract quickly in people suffering severe allergic reactions.

The 0.3 mg pens are intended for those who weigh 30 kilograms or more (approximately 66 pounds or more).

Repeated shortages of the life-saving EpiPen has "moved from an inconvenience to a concern,'' says Food Allergy Canada.

The national advocacy group was among those alarmed by yet another announcement from Pfizer that its epinephrine auto-injector is in short supply, with executive director Jennifer Gerdts saying the latest shortfall comes just when it's needed most.

“The month of August … is a key peak demand time for our audience given that it’s back-to-school,” says Gerdts, noting that many schools request students have an extra EpiPen onsite as a backup.

“This is the time at which they are looking to refill prescriptions.”

Pfizer Canada says that the current shortage is due to manufacturing problems with the 0.3 mg format.