Catalyst Rx, the pharmacy benefit management (PBM) subsidiary of Catalyst Health Solutions, Inc. (NASDAQ: CHSI), and Medical Card Systems, Inc. (MCS) announced today that they have reached agreement for Catalyst Rx to continue managing the pharmacy benefits for MCS' commercial and Medicare Part D business lines through December 31, 2012.

MCS' commercial business is comprised of approximately 138,000 lives and the Medicare business consists of approximately 120,000 lives. Under the new terms, which will be further set forth in definitive agreements, certain delegated services being administered by Catalyst will be transitioned to MCS. The term of the commercial agreement may, at MCS' option, be extended for an additional two years through December 31, 2014.

?We thank MCS for the opportunity to continue managing their pharmacy benefits. Through personalized service, quality and efficiency in clinical care, MCS is the leading health plan in Puerto Rico . . . we are fortunate to be a part of MCS' product offerings. Catalyst will continue to provide MCS with transparent, innovative, and lowest net cost solutions,? said David T. Blair, Chief Executive Officer of Catalyst Health Solutions, Inc.

?We are pleased to put this dispute behind us and look forward to continuing our relationship with Catalyst,? said Mark Rishell, Chief Financial Officer and Co-Chief Executive Officer of MCS.

The Catalyst management team will provide additional detail on this announcement and other corporate developments in conjunction with its third quarter investor call scheduled for November 4, 2010 at 10:00 am (ET).

About Catalyst Health Solutions, Inc. (www.chsi.com)

Catalyst Health Solutions, Inc. is built on strong, innovative principles in the management of prescription drug benefits and provides an unbiased, client-centered philosophy resulting in industry-leading client retention rates. The Company's subsidiaries include Catalyst Rx, a full-service pharmacy benefit manager serving more than 7 million lives in the United States and Puerto Rico; HospiScript Services, LLC, one of the largest providers of pharmacy benefit management services to the hospice industry; and Immediate Pharmaceutical Services, Inc., a fully integrated prescription mail service facility in Avon Lake, Ohio. The Company's clients include self-insured employers, including state and local governments, managed care organizations, unions, hospices, third-party administrators and individuals.

This press release may contain ?forward-looking statements? as defined in the Private Securities Litigation Reform Act of 1995. These statements involve a number of risks and uncertainties that might materially affect our results, particularly those risks referred to in our Annual Report on Form 10-K for the year ended December 31, 2009, and in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2010, under ?Item 1A. Risk Factors.? Readers are urged to carefully review and consider the various disclosures made in our Annual Report on Form 10-K, our Forms 10-Q, and our other filings with the Securities and Exchange Commission that attempt to advise interested parties of the risks and uncertainties that may affect our business. Catalyst Health Solutions, Inc. does not undertake any obligation to update forward-looking statements, whether as a result of new information, future events, or other developments.

Catalyst Health Solutions, Inc.
Hai Tran, 301-548-2900
Chief Financial Officer
htran@chsi.com