Shares of health-care data company IMS Health Inc. (RX) fell on Friday before thinning back to more meek losses amidst concerns that a US Senate health-care change proposed on Thursday could cut into the company's earnings.

Yesterday, Democrats established an alteration to health-care legislation in the Senate that would forbid drug-makers from using prescription records to direct marketing to doctors.

IMS dropped by $1.31, or 6.1 percent, to $20.05 in New York Stock Exchange composite trading. The amendment, backed by Democratic Sens. Herb Kohl and Dick Durbin, would ban the sale of doctors' prescribing records for marketing purposes.

Companies like IMS get information from pharmacies and sell it after altering it to drug companies that use it to steer the way they market drugs to doctors.

"Without such information, it is much more difficult to communicate with physicians about best treatment practices and updated safety warnings for medicines," the company said.

Owen Blicksilver, a spokesman for TPG referred all questions to IMS.

Analysts said investors may be concerned on Friday that the Senate proposal may rush the deal, but William Blair analyst John Kreger dismissed those fears by stating, "It's good politics, but not really good policy."

And even if the proposal does become law, he doesn't think it will have more than a 5 per cent impact on IMS's earnings.

Shielding the prescribing practices of physicians has the potential to harm patients, IMS said. If the Senate takes up the issue at all, it should follow the US House that called for a study of data- mining without an outright ban, the company said.