Canadian pharmacists fear changes to medication purchasing regulations in the U.S. will lead to further drug shortages north of the border during an already difficult period.

On Wednesday, the U.S. Department of Health and Human Services announced that it will allow American patients and businesses to purchase drugs from Canada, where certain medications can be 10 times cheaper due to price controls.

Dean Miller, president and CEO of Whole Health Pharmacy Partners, told CTV News that some Canadian pharmacies are already experiencing shortages of more than 1,000 medications, amounting to the worst shortage he’s seen in his more than 30-year career.

While questions swirl about how exactly this policy will work in principle, Miller worries that with more Americans heading north for medicine, the drug shortages will only increase.

“It’s even going to get worse, to the point where people may die from just not being able to get their medications,” he said in an interview from Wellth Pharmacy in Toronto. “Medications here are stocked and manufactured for Canadians, not for a country that’s 10 times as big as us.”

Russell Thomas of New Westminster, B.C. already struggles to find a supplier for Type 2 diabetes medication. He said the last time he needed to fill a prescription, the local Safeway only had about a month’s worth of pills in stock, but he was able to scrounge up another 100 pills by checking every Safeway in town.

“Shoppers, Rexall, nobody’s got it,” he said. “So where am I supposed to go? What am I supposed to do?”

Joelle Walker, the vice president of public affairs for the Canadian Pharmacists Association, worries that on top the potential drug shortages, the change in regulation could also increase the prices of drugs for Canadians.

“Pharmacists are there every day, they want to help patients that walk through their doors,” she said. “Our concern is what policies can be put in place to make sure that we’re not seeing massive amounts of medications that are designed for the Canadian market that actually end up going to the United States?”

Walker added that her organization is hoping to have a meeting with the federal government to discuss what regulations can be put in place to prevent any potential harm for Canadians.

The office of Health Minister Ginette Petitpas Taylor said in an emailed statement that they are proud of Canada’s health care system and that the U.S.’ interest in Canadian medications is evidence of their “commitment to more affordable prescription drugs.”

“Ensuring that Canadians have access to the medicines they need is one of our top priorities,” the statement continues. “We constantly monitor Canada’s drug supply, will be working closely with health experts to better understand the implications for Canadians and will ensure there are no adverse effects to the supply or cost of prescription drugs in Canada.”

The cost of pharmaceuticals in the U.S. has become an issue for the upcoming presidential election. Over the weekend, Democratic presidential candidate Bernie Sanders crossed the U.S.-Canada border with dozens of Americans who were buying cheaper insulin.

U.S. President Donald Trump promised to make medications more affordable for Americans during his 2016 campaign.