By James Vicini

WASHINGTON (Reuters) - The Supreme Court said on Friday that it would decide whether a state law restricting commercial access to information about prescription drug records violated constitutional free-speech rights.

The justices agreed to review a data mining law adopted in 2007 in Vermont that prevented the sale, transmission or use of prescriber-identifiable information for marketing a prescription drug unless the prescribing doctor consented.

The law was challenged by three companies -- IMS Health, Verispan and Source Healthcare Analytics, a unit of Dutch publisher Wolters Kluwer -- that collect and sell such data and by a trade group for pharmaceutical manufacturers.

A U.S. appeals court based in New York struck down the Vermont law for infringing on commercial free-speech rights in violation of the Constitution's First Amendment.

Vermont, Maine and New Hampshire have been the only states to adopt such laws, though similar measures have been proposed in the last three years in about 25 states across the country.

Vermont pharmacies must collect information that includes the prescribing doctor's name and address, the name, dosage and quantity of the drug, the data and place where the prescription has been filled and the patient's age and gender.

The law restricted pharmacies from disclosing the data and gave prescribing doctors the right to consent before their identifying information in the drug records is sold or used in marketing.

Pharmaceutical manufactures use data about a doctor's prescribing habits to better inform their drug salespeople when they visit physician offices to market certain products.

Companies that collect the data have said the information about doctors' prescribing patterns can be used to help monitor safety issues of new medications, reduce costs and for research purposes like studying treatment outcomes.

The law's supporters have said it helped protect medical privacy and control health care costs by promoting genetic drugs over more expensive brand-name drugs.

Vermont, the three companies and the Pharmaceutical Research and Manufacturers of America all urged the Supreme Court to decide the issue because of conflicting lower court rulings.

While the appeals court in New York struck down the Vermont law, a federal appeals court based in Boston upheld the similar laws adopted by New Hampshire and Maine.

The Supreme Court is expected to hear arguments in the case in April, with a ruling due by the end of June.

The Supreme Court case is Sorrell v. IMS Health, No. 10-779.

(Editing by Steve Orlofsky; editing by Carol Bishopric)