WASHINGTON – Urged on by the U.S. government, Canadian officials are cracking down on companies, pharmacists and physicians within their borders that help provide Americans – including thousands of Mainers – with cheaper prescription drugs.

But complex jurisdictional issues guarantee the enforcement won’t be that quick or that simple.

Although the U.S. Food and Drug Administration has escalated its threats to shut down companies exporting drugs to America, FDA Commissioner Mark McClellan said there are “no automatic mechanisms set up between our countries.”

“We have to have those discussions,” he said. “We have to work together to identify where our laws match up and where they don’t.”

High-level U.S. and Canadian health officials have met several times in recent weeks to coordinate their attack on the booming Internet pharmacy trade.

But the FDA has no jurisdiction in Canada. Health Canada, the federal agency that regulates drugs, has only broad authority over drug safety issues.

Instead, most direct enforcement over pharmacists and physicians co-signing and filling prescriptions for American patients falls to separate organizations in each province, where regulations vary.

“The challenge is the practice taking place is illegal in the U.S., and the U.S. has enforcement problems, but in Canada the activity of the pharmacists follows the letter of the law,” said Canadian Pharmacists Association Executive Director Jeff Poston. “And they don’t have that many legal or policy levers to play with at the moment.”

Medical organizations in Canada oppose the Internet trade, but acknowledge enforcement is tricky.

“It’s legal for a [Ontario] pharmacist to fill the prescription if an Ontario doctor co-signs,” said Ontario Pharmacists Association Vice President Ruth Mallon. Pharmacists could be in trouble, she said, if regulators could prove they knew a doctor didn’t see the patient and was part of an Internet operation.

An estimated million-plus Americans order drugs from Canada. Pharmacies across Maine have felt the pinch of lost sales because thousands of Mainers are buying cheaper drugs over the Internet from Canada.

Affiliated Healthcare Systems of Bangor estimates that just fewer than 5,000 Mainers order Canadian drugs through its “Canada Rx” mail order program, while an unknown number go through larger chains such as Rx Savings Center.

Cash-strapped cities and states across the United States are exploring ways to save money by allowing their workers to buy the much cheaper Canadian drugs. Also, members of Congress are pressuring the FDA to find ways to sanction the cross-border purchases.

Under Canadian law, only licensed pharmacists may dispense prescription drugs. Most provincial standards require physicians to have a doctor-patient relationship with someone before prescribing drugs for that person.

But because each province’s laws vary, Internet companies say they are operating within the law.

Generally in Internet sales, U.S. patients send their prescriptions to the Canadian company, which has it reviewed and co-signed by a Canadian physician, then filled by a licensed Canadian pharmacy.

“We’re in total compliance with Health Canada at this time – we’re not breaking any laws in Canada or in the United States,” said Anthony Howard, president of CanaRx, the Ontario-based company providing prescription drugs for employees in Springfield, Mass., the first city to allow workers to get drugs from Canada.

The FDA concluded that CanaRx is illegally exporting drugs, and has asked Canadian authorities to investigate. Deanna Williams, head of the Ontario College of Pharmacists, confirmed that regulators are “looking into” pharmacies that do business with CanaRx to determine whether they are violating provincial law.

Other enforcement in Canada is on the rise.

In a letter last week to provincial regulators of pharmacists and physicians, Health Canada stressed the importance of enforcing laws on Internet pharmacies.

The Ontario College of Physicians and Surgeons is investigating a physician for writing prescriptions for U.S. residents without seeing the patients. In Manitoba, four physicians were censured last week for co-signing prescriptions for American patients.

Canadian officials bristle at suggestions that their drugs are unsafe, insisting their approval process is as rigid as the FDA’s. But they also worry the cross-border trade will trigger a potential drug shortage, increase prices and raise questions about their drug safety.

Four major drug manufacturers increased prices in Canada in the past three months, and companies are threatening to stop selling to pharmacists caught supplying drugs to U.S. residents.

But the Internet companies say they’ve seen no drug shortage, and they are not folding.

“What they’ve got to understand is, we’re not going away,” said Howard. “We’re going to stick to this until the laws are changed.”

A growing number of lawmakers agree.

“The FDA can try to lip-sync the pharmaceutical industry’s line, but people are going to continue to go over the border to buy the drugs they need at the prices they can afford,” said Rep. Rahm Emanual, D-Ill.

And that, said Canadian officials, is a problem no amount of enforcement may correct.

“We work hard to protect the public against pharmacies that are not following the law,” said Williams. “But we can’t protect them against themselves.”