Following Health Canada’s warning that the country could run out of EpiPen injectors in August, Canadians with life-threatening allergies need to be prepared for the shortage.

On Monday, the health agency said that EpiPen manufacturer Pfizer Canada had advised them that its supply of adult-dose 0.3 mg auto-injectors was expected to be “very limited” at pharmacies in August, due to a manufacturing issue. The company said it would still be able to continue to supply the 0.15 mg EpiPen Jr auto-injectors designed for children, but said that supply was also limited and would be carefully managed at pharmacies.

EpiPen and EpiPen Jr injectors provide users with a single dose of epinephrine when they are suffering from anaphylaxis, a life-threatening allergic reaction.

Pfizer Canada said it doesn’t expect the next shipment of adult-dose auto-injectors until the end of August. In the meantime, here’s what Canadians who rely on EpiPens can do:

Check the expiry date:

Patients are being advised by Health Canada and pharmacists to check the expiry date of any EpiPen injectors they already own.

According to Pfizer Canada, the product is good until the last day of the month that’s indicated. For example, if the injector has an expiry label that reads “AU 18,” it means the product expires on the last day of August 2018.

Pfizer Canada said all new EpiPen injectors should have a minimum of 12 months before the expiry date.

If the EpiPen is not expired yet, Health Canada and Pfizer Canada are asking allergy sufferers to avoid going to the pharmacy to stock up on more injectors so that other patients in need will be able to get one.

If the EpiPen is expired:

For patients with an expired EpiPen, it’s recommended they speak with their doctor or pharmacist about obtaining a new one. If there are no new injectors available, patients should hold on to the expired EpiPen they already own.

How to store an EpiPen:

Pharmacist Sujay Khiroya in Nova Scotia told CTV Atlantic that an EpiPen’s efficacy, even after its expired, will depend on how long has elapsed and how it was stored.

Pfizer Canada advises users to store EpiPen injectors in its carrier tube with the safety release on until the product is used. The injectors should be stored at room temperature and shouldn’t be kept in the refrigerator.

EpiPen injectors can be exposed to temperatures between 15 C and 30 C. They shouldn’t be left in vehicles during hot or cold weather, the company states.

It’s also recommended that patients protect their EpiPen from light and avoid submerging it in water.

Patients are also instructed to peek through the viewing window on the EpiPen periodically to ensure the solution inside of it is not brown, discoloured, or cloudy, which indicates it may have come into contact with oxygen, extreme temperatures, light or some foreign element such as metal.

If that’s the case, Pfizer Canada advises users to replace the EpiPen with a new one.

During an emergency:

In the event of an emergency, Health Canada advises patients with an expired EpiPen to use them anyway and call 911 immediately.

While Pfizer Canada doesn’t recommend using an EpiPen injector past its expiry date on its website, Health Canada and pharmacists say the products may still be effective and suggest using them if there isn’t a new one available.

A 2017 study conducted by a team of researchers at the University of California, San Diego, and published in the Annals of Internal Medicine, tested 40 expired EpiPens and EpiPen Jrs and found they retained at least 90 per cent of their stated epinephrine concentrations 29 months after the expiry date. Even four years after the expiry, the EpiPen injectors contained 84 per cent of their epinephrine concentrations.

“Our data show that EpiPen products can retain substantial amounts of epinephrine well beyond their expiration dates,” the study’s authors wrote in the journal. “Although we observed declining concentrations of epinephrine over time, we expect that the dose available 50 months after expiration would still provide a beneficial pharmacologic response.”

No other alternative:

EpiPen is currently the only supplier of epinephrine auto-injectors in Canada, even though other companies have secured approval from Health Canada to sell similar products in the country.

Kaleo Pharma, Taro Pharmaceuticals, Valeant Canada and Lincoln Medical have all received authorization from Health Canada, but they haven’t begun distribution.

Health Canada’s chief medical adviser, Dr. Supriya Sharma, told CTV News that they’re trying to “encourage” other companies to market their products in Canada.

“The decision to market a product in Canada is at the discretion of the manufacturer,” Sharma said. “We would like those companies to bring additional products to Canada. This is a situation where we don’t have alternatives.”

Until other companies offer alternatives, EpiPen auto-injectors are the only products available to Canadians.