EPOC Epocrates, Inc. (MM)

The following materials were first used by Epocrates, Inc. on January 7, 2012, (Pacific Time) in discussing the proposed transaction referred to in the material below with its employees, customers, investors and/or vendors and Epocrates may use these materials in the future for similar purposes:

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Press Release

As one of our loyal members, we wanted you to be among the first to hear some very exciting news.

athenahealth, a leading provider of cloud-based electronic health record (EHR), practice management, and care coordination services to medical groups and health systems, has signed an agreement to acquire Epocrates.

We see this transaction as a natural evolution for Epocrates as we share a mission to set a new standard for how healthcare providers obtain and interact with information at the point of care. Epocrates’ deep mobile expertise and focus on delivering the right healthcare information at the right time, combined with athenahealth’s focus on clinical workflow and operational efficiency, will truly benefit all of our members.

Our vision is even more secure now that we have aligned with athenahealth. Together, we will pioneer new mobile workflows to improve provider efficiency and support care delivery outcomes; initial efforts will focus on expanding our set of look-up tools; we’ll also work to launch care coordination and provider-to-provider communication services.

We want you to know that you will not see any changes to your relationship with Epocrates. athenahealth’s commitment and go forward mission with Epocrates is to preserve all that you have come know, trust, rely upon and love. The same products and people you are working with now—the ones who are helping you transform health care for your patients—are the same ones you will be working with tomorrow.

For further details of this news, please follow this link.

As always, feel free to contact me or the support team with any questions.

Regards,

President, CEO & interim CFO

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Additional Information and Where to Find It.

In connection with the acquisition of Epocrates, Inc. (“Epocrates”) by athenahealth, Inc. (“athenahealth”) pursuant to an Agreement and Plan of Merger (the “Merger Agreement”), Epocrates will file with the U.S. Securities and Exchange Commission (the “SEC”) a proxy statement and other relevant materials in connection with the proposed transaction. Epocrates will also mail the proxy statement to Epocrates stockholders. athenahealth and Epocrates urge investors and security holders to read the proxy statement and the other relevant material when they become available because these materials will contain important information about athenahealth, Epocrates, and the proposed transaction. The proxy statement and other relevant materials (when they become available), and any and all documents filed with the SEC, may be obtained free of charge at the SEC’s web site at www.sec.gov. In addition, free copies of the documents filed with the SEC by athenahealth will be available on the “Investors” portion of athenahealth’s website at www.athenahealth.com. Free copies of the documents filed with the SEC by Epocrates will be available on the “Investor Relations” portion of Epocrates’ website at www.epocrates.com. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE PROXY STATEMENT AND THE OTHER RELEVANT MATERIALS WHEN THEY BECOME AVAILABLE BEFORE MAKING ANY VOTING OR INVESTMENT DECISION WITH RESPECT TO THE PROPOSED TRANSACTION.

athenahealth, Echo Merger Sub, Inc. (“MergerSub”), Epocrates, and their respective executive officers and directors may be deemed to be participants in the solicitation of proxies from the security holders of Epocrates in connection with the Merger. Information about those executive officers and directors of athenahealth is set forth in athenahealth’s proxy statement for its 2012 annual meeting of stockholders, which was filed with the SEC on April 26, 2012, and is supplemented by other public filings made, and to be made, with the SEC. Information about those executive officers and directors of Epocrates and their ownership of Epocrates common stock is set forth in Epocrates’ proxy statement for its 2012 annual meeting of stockholders, which was filed with the SEC on August 30, 2012, and will be included in Epocrates’ proxy statement to be filed with the SEC in connection with

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the proposed transaction as described above, and is supplemented by other public filings made, and to be made, with the SEC. Investors and security holders may obtain additional information regarding the direct and indirect interests of athenahealth, MergerSub, Epocrates, and their respective executive officers and directors in the Merger by reading the proxy statements and the other filings and documents referred to above. This communication does not constitute an offer of any securities for sale.

Forward Looking Statements

This communication includes “forward-looking statements” within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include statements relating to the consummation of the Merger, and other statements that are regarding future events and not historical facts. The forward-looking statements included herein represent the current judgment and expectations of the respective companies, but actual results are subject to risks and uncertainties and could differ materially from those expressed or implied by forward-looking statements. Neither Epocrates nor athenahealth intend to update any of these forward-looking statements or publicly announce the results of any revisions to these forward-looking statements, other than as is required under the federal securities laws.

The potential risks and uncertainties include: uncertainties as to the timing of the Merger; the risk that Epocrates stockholders fail to approve the transaction; the risk that competing offers will be made; and the possibility that various closing conditions for the transaction may not be satisfied or waived. These and other risks and uncertainties, which are described in more detail in Epocrates’ and athenahealth’s most recent Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q filed with the SEC, could cause actual results and developments to be materially different from those expressed or implied by any of these forward-looking statements.

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