The US Supreme Court this week heard arguments for and against attempts by the state of Vermont to block the use of physician prescribing data for marketing purposes – with some justices apparently leaning towards the view that to do so would restrict free speech.

Vermont’s law was overturned on a challenge by IMS Health, SDI and Source Healthcare Analytics – three companies who collect and sell prescribing data, but who supported Vermont’s request for a Supreme Court review of the decision.

The companies said at the time: “We believe the justices will agree with the Court of Appeals that laws like this one violate the First Amendment right of free speech.”

And it seems some do, according to a New York Times report. Vermont believes that by hampering drug companies’ marketing efforts it can lower healthcare costs through more effective promotion of cheaper generic alternatives.

But this runs up against a basic First Amendment problem, the Times says, quoting Justice Ruth Bader Ginsburg: “You can’t lower the decibel level of one speaker,” she said, “so that another speaker, in this case the generics, can be heard better.”

A ruling is expected by June.

Update: A full transcript of the Supreme Court hearing can be found online here.