High prices for prescription drugs have prompted widespread attempts to import drugs from Canada, where government controls make prices 20-80% lower than in the United States.
The lobby group the Pharmaceutical Research and Manufacturers of America (PhRMA), says that imports carry risks but admits that the US healthcare system leaves too many patients without access to the medicines they need.
Although drugs account for only 10% of healthcare costs, the amount has doubled since 1980 and drug prices have tripled. An estimated one to two million Americans buy prescription drugs from abroad.
The American Association of Retired People, which has 35 million members over the age of 50, reported that some of its members coped by buying less food, sharing their drugs, using other people's leftover prescriptions, or, most often, going without their medications.
More than a third of the people surveyed for the association said they bought drugs from Canada. Older people can get cheaper drugs from discount plans from drug companies and elder associations, but few are aware of these plans.
Democratic mayor Michael Albano of Springfield, Massachusetts, set the trend when he set up a plan to import Canadian drugs for city employees and retired citizens and their dependants in July, in a bid to save the city as much as $9m (£5.4m; €7.8m) a year.
Now the governors of states bordering Canada are planning to follow suit. Governor Rod Blagojevich of Illinois estimated that the state would save $91m by buying drugs from Canada.
"America is subsidising the rest of the world. We are paying a lot more for prescription drugs than we should," Governor Tom Vilsack of Iowa told the Associated Press. He estimates that Iowa would save $10m.
The Food and Drug Administration is trying to stop the practice on safety grounds, and the National Association of Boards of Pharmacy has warned: "Considering current world events, we believe it is dangerous to purchase medications from abroad."
Jeff Trewhitt, spokesman for the Pharmaceutical Research and Manufacturers of America, told the BMJ that the organisation was "deeply concerned." Patients may not receive the drugs ordered or the drugs may be adulterated, counterfeit, or ineffective, he said.
Federal judges have already shut down an Oklahoma pharmacy chain that imported drugs from Canada and another chain in the north east.
Meanwhile, bills to include drug coverage in Medicare, the health insurance programme for elderly people, have stalled in Congress, and the impasse may not be resolved before the Thanksgiving recess on 21 November.
Access to prescription drugs will be discussed at the free trade conference in Miami later this month.