Agreement Addendum

Exhibit 10.18

[*] Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4) and 230.406

Agreement Addendum

        This addendum pertains to the agreement originally dated October 27, 2003 between Mark K Dambro, MD, PA a Texas Corporation, and Epocrates, Inc. (Licensee).

        The following addendum is Made and entered into this January 31, 2007 and outlines the following Changes:

Amendments to Contract for 5MCC Originally Dated 10/27/03

Change In—Ownership of Licensing Agreement

        The above referenced contract is now amended to be between Wolters Kluwer Health, Inc., Lippincott Williams and Wilkins, a Delaware Corporation, with offices at 351 West Camden St., Baltimore, MD 21201 ("Editor") and Epocrates, Inc. ("Licensee").

Change In—Section 1: License Granted

        The original agreement shall be amended to clarify the license granted as follows:

        Editor hereby grants to Epocrates on the terms and conditions set forth herein, during the term of this Agreement a non-exclusive, non-transferable, worldwide, royalty bearing right and license to market, display, demonstrate, use and support the Data (hereto the "Data"), in electronic format for use on Personal Digital Assistants (PDA's). All other platforms will be considered and agreed upon on a case by case basis. Publisher retains all rights in and to the Data and Epocrates shall have no rights thereto except as expressly granted herein. Epocrates license to modify the Data shall be limited to modifying the Data for such coding purposes as may be reasonably necessary for the fulfillment of the Agreement and to fit the format and look and feel of the Epocrates Product and to promote the Epocrates Product, provided that Epocrates does not modify or edit the text of the Data by addition, deletion, or other modification that would alter its substance or meaning, without Publisher's prior written consent. In no event shall Epocrates have the right to (a) publish the Data in printed format, or (b) sub-license the Data to third-parties of any kind except in connection with a license to the Epocrates Product as allowed under this Agreement.

Change In—Section 8: Term

        The term of this renewal shall be for [*] years commencing on the effective date of [*] through [*], unless terminated in the manner provided for in the original agreement.

[*] Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4) and 230.406

Change In—Addendum A: Compensation & Royalties

        The following changes will be made to the Compensation and Royalty structure of the original agreement to be effective for sales made as of 11/1/2007:

• •

  For each product (containing all or any part of the Clinical Data) sold or licensed to an end-user, the Licensee shall pay the Editor a royalty of [*]% of the selling price. For bulk sales (sale executed to a single customer—not including any subsidiary or other entity owned or managed by the Licensee) the following discount structure shall apply:

        The following clarifications to the Compensation and Royalty structure of the original agreement are hereby added to the agreement:

• •

  Royalties shall be due and payable to Editor upon activation of subscription by customers. If the content is purchased as part of an off-line license (defined as a sponsored subscription or sale of gift certificate) then royalty shall be due and payable to Editor when the license code is activated.
  
  

  •

  Royalties due to Editor shall be net of returns and cancellations made within a 30 day period after activation, and net of sales, use, value-added or similar taxes.

        All other terms for this addendum are as per the original agreement dated 10/27/2003 and the amendment to the original agreement dated 11/10/2005.

        AS WITNESS AND SEAL OF THE PARTIES HERETO:

[*] Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4) and 230.406

AMENDMENT
TO LICENSE AGREEMENT

        This Amendment, effective as of November 10, 2005, amends the license agreement ("Agreement") dated as of October 27, 2003, entered into by and between Epocrates, Inc., a California Corporation, with offices located at 1800 Gateway Drive, Suite 300, San Mateo, California 94404 ("Epocrates") and Mistletoe Health Partners, PA (previously Mark R. Dambro, MD, PA), a Texas corporation, with offices located at 1350 S. Main St., Suite 1400, Fort Worth, Texas 76104 ("Editor').

AMENDMENT

        In consideration of the mutual representations and covenants set forth below, and other valuable consideration, the receipt and sufficiency of which is hereby acknowledged, Epocrates and Editor agree to amend the Agreement by adding the following paragraphs to the end of Addendum A:

• Editor acknowledges that the computer application marketed by Epocrates under the Epocrates Sx™ brand ("Sx") is a separate product from the computer application containing the Clinical Data and marketed by Epocrates under the Epocrates Dx™ brand ("Dx"), and that Sx is not a product containing Clinical Data for which Editor is to be paid Royalties under the Agreement. Consequently, when Epocrates licenses both Sx and Dx to an end user, the Royalties payable to Editor shall be based on the portion of the license fees paid by the end user attributable to Dx. By way of example, if Epocrates is licensing Dx alone to end users for a license fee of [*] dollars ($[*]) per year and concurrently licenses a package of Sx and Dx together ("Package License") for an annual license fee of [*] dollars ($[*]) per year, then Epocrates would owe Editor Royalties under the Agreement on [*] ($[*]) of the fees for the Package License.

  If Epocrates elects to offer the Package License and cease offering a license to Dx alone, then the portion of the license fees received by Epocrates from an end user will be allocated between Dx and Sx in the same proportion determined in previous paragraph at the time Dx ceases to be licensed alone. By way of example, if the license fees for Dx and the Package License at the time Epocrates stops licensing Dx alone are as set forth in the example in the previous paragraph and Epocrates subsequently licenses the Package License for a fee of [*] dollars ($[*]), then the portion of the [*] dollar license fee attributable to Dx would be calculated as follows:

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    Portion of fee attributable to Dx at the time it is no longer licensed alone = $[*]/$[*] = [*]
    
    

    •

    Portion of Package License fee attributable to Dx after increase = [*] × $[*] = $[*].

        All capitalized terms used, but not defined, in this Amendment shall have the meanings attributed to such terms in the Agreement.

        Except as specifically modified by this Amendment, all terms and conditions of the Agreement shall remain in full force and effect.

[*] Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4) and 230.406

        IN WITNESS WHEREOF, the Epocrates and Editor have caused this Amendment to be executed by their duly authorized representatives as of the date first set forth above.

[*] Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4) and 230.406

License Agreement

        This Agreement is made this 27 ^th  day of October, 2003 ("Effective Date") between Mark R Dambro, MD, PA a Texas Corporation ("Editor"), and ePocrates, Inc. ("Licensee").

         Whereas , the Editor has developed and maintains a copyrighted database of medical information ("Clinical Data" or "Data") as published in the book known as Griffith's: 5-Minute Clinical Consult; and

Description of Clinical Data

• • • The Clinical Data consists of approximately 1200 med