A long legal battle over advertising drugs directly to consumers is drawing to a close in Canada’s Superior Court.

The Canadian media giant Canwest is suing the federal government, claiming that the prohibition on advertising prescription drugs directly to the public is a contravention of the constitutional charter guaranteeing free speech.

In a document tendered to the court Canwest’s legal team has described the prohibitions as “paternalistic and anachronistic.” It argues that “truthful, balanced and fair statements containing information that is useful to patients cannot be curtailed” under the Canadian Charter of Rights and Freedoms.

The summary of the media company’s position, given in a 67 page “factum” provided to the court, is that the Canadian government already allows its citizens to be “bombarded” with direct to consumer advertisements in United States television, magazines, and the internet, “all of which the government permits to be distributed in Canada without restriction.”

It is estimated that drug companies collectively spend more than US$4bn (£2.7bn; 3bn) a year on such advertising in the United States. Although the industry is currently allowed to freely advertise prescription drugs directly to consumers only in the United States and New Zealand, it is pushing strongly for liberalisation of the ban in Europe, framing the aim as providing “information,” not advertising.

Arguing against any lifting of the prohibition in Canada, the federal government has told the Superior Court that the current restrictions do not impinge on the freedom of speech of media companies and that such restrictions are in place to protect the public’s health. The factum from Canada’s attorney general says that the benefits of such advertising are theoretical but unproved and that “the evidence of harm is much stronger and the known and potential harms outweigh any possible benefits.”

Responding to Canwest’s argument that advertisements will educate and inform consumers, the attorney general’s statement says that the purpose of the advertisements “is not to provide information, but is to convey a message intended to persuade, and which is likely to mislead and/or confuse the listener.”

Unusually the court has given leave to an ad hoc coalition of interest groups, including unions and healthcare groups, to intervene in the case. In its own factum this group argues that advertisements subject patients to “biased, misleading or deceptive” claims, exposes them to greater risk of side effects, damages the doctor-patient relationship, unnecessarily increases the overall costs of drugs, and neglects non-drug solutions to health problems.

The lawyer representing the coalition, Steven Shrybman, says that it has put evidence before the court that direct to consumer advertising disproportionately targets conditions affecting women. “Much of what is conveyed to women about drugs is ill founded,” he said.

Speaking from a personal perspective, the legal counsel for Canwest, Martin Teplitsky, told the BMJ that he disagreed with the “proselytising” of those who believe that society is overmedicated and said that he saw advertisements as educating and informing. “When we talk openly about things like erectile dysfunction, sexually transmitted diseases, and depression, that’s a good thing. It’s good for society, not bad.”

The case is scheduled to have final hearings in the Superior Court in June.

BMJ 2009;338:b1912