FATIMA HUSSEIN WASHINGTON — Millions of Americans who buy cheap drugs from Canada could soon lose access when a customs rule goes into effect later this month, a change that has sparked opposition from Democrats and some Republicans with the cost of living a top issue for voters ahead of midterm elections.

The rule applies to a swath of goods beyond drugs and is intended to collect tariffs and prevent illegal drugs from coming into the U.S. It comes as President Donald Trump has made lowering drug prices a top target in addressing soaring healthcare costs , and critics say the rule will hurt patients seeking affordable medicine.

“The issue is a matter of life and death for me,” said Susan Hooper, a 75-year-old Toledo, Ohio, resident who has been on oxygen for 14 years and takes two daily medications purchased through a Canadian pharmacy that are not available in the U.S.

The U.S. Customs and Border Protection rule targets the de minimis exemption , which previously allowed shipments valued under $800 to pass through customs more easily. As of Oct. 22, that exemption will be indefinitely suspended, and medications mailed from outside the U.S. will require additional data and a bond guarantee.

The rule puts added fees and registration requirements on low-value shipments that previously entered the U.S. duty-free — on everything from textiles to toys — but the people who could see the most significant impacts are those who buy their cheap drugs from across the border.

And while the rule doesn’t specifically target Canadian drugs — it applies to international mail generally — the practical consequence could be delays, refusals or substantially more difficulty getting their medications delivered.

Roughly 2.3 million Americans buy their drugs abroad, according to a 2020 study by JAMA Network.

The Trump administration has made lowering drug prices a priority in its bid to show Americans that it is tackling soaring costs. Trump, a Republican, has struck multiple most-favored-nation drug deals with pharmaceutical firms and has launched the discounted-drug website TrumpRx , among other steps.

Federal data from this summer showed that U.S. prescription drug prices were down 3.1% from a year ago , the steepest year-over-year drop since 1963. Trump has sought to take credit for the steep decline, but the real picture is more complicated , and experts say factors beyond the president’s policies likely contributed more to the drop. Advocates say the rule will hurt patients seeking affordable medicine.

Ken Hunter, executive director of the Campaign for Personal Prescription Importation, which advocates on behalf of Americans who access the Canadian drugs, said those who have enjoyed the lower drug prices from across the northern border may not benefit from Trump’s drug pricing moves.

“There has been a lot of talk of lowering drug prices, but in many cases it doesn’t cover all drugs for all people for all conditions,” he said.

Hunter warned that costs will explode for some medications after his organization conducted a study in August looking at 10 of the most commonly prescribed medications imported from Canada.

He cited Eliquis, a prescription blood thinner used to prevent and treat dangerous blood clots. A three-month supply of 180 5-mg pills would cost $565 from a mail order Canadian pharmacy. The same medication would cost roughly $1,017 from Amazon’s pharmacy arm or $1,029 from GoodRx.

“I’ve had so many of our members calling me and telling me, ‘I don’t know what I’m going to do,’” Hunter said. “We really need someone to step forward and say, ‘We really need this to stop.’”Allison Schuster, a White House spokesperson, said in a statement that Trump “remains dedicated to lowering the cost of prescription drugs,” citing the most-favored-nation deals.

“The Trump administration continues working to ensure Americans have access to low-cost pharmaceuticals across the board,” Schuster said.

The Trump administration could drop the rule, alter it or decide not to enforce it. Lawmakers on both sides of the aisle have demanded answers to how the administration will protect access to affordable care for people who get their drugs from over the border.

Three Florida Republican members of Congress wrote to the administration last month expressing concern about how the rule would impact their constituents, who, unlike residents of border states, are unable to easily travel to Canada to buy the drugs.

Florida has separately crafted a Canadian prescription drug importation program with authorization from the federal government , but that initiative has stalled.

Customs and Border Protection and the Food and Drug Administration “must ensure that Floridians simply seeking relief from high drug prices will not be inadvertently impacted by the rule,” said the letter signed by Florida Reps. Aaron Bean, Gus M. Bilirakis and C. Scott Franklin.

A group of more than 70 Democrats last week sent a letter to health and immigration enforcement officials, asking them to pause the new rule unless they could provide assurances that prescription medicines meant for personal use would be able to enter the U.S.

“Americans should not lose access to affordable medicines simply because the government has better information about packages entering the country,” the letter said. Representatives from CBP did not respond to requests for comment.

Hooper, who has serious drug allergies, said her medications have already increased in price since the Trump administration imposed additional tariffs on Canada in August.

She says Theophylline, a medication that relaxes her airways and is bought in Canada, used to cost $85 with shipping. It now costs $141 because of tariffs. And her Foradil bronchodilator for asthma, which used to cost $151, now costs $273.

Hooper said she will find a way to manage through the change. Until then, she said, she’s been in a rush to stockpile.