ADDENDUM No. 4 TO AMENDED AND RESTATED MASTER SERVICES AGREEMENT

EXHIBIT 10.63

ADDENDUM No. 4 TO

AMENDED AND RESTATED MASTER SERVICES AGREEMENT

THIS ADDENDUM No. 4 (the “Addendum”) to the AMENDED AND RESTATED MASTER SERVICES AGREEMENT dated as of May 31, 2005, as amended (collectively, the “Agreement”), by and between EXPRESS SCRIPTS SPECIALTY DISTRIBUTION SERVICES, INC. (“ESSDS”) and ORPHAN MEDICAL, INC. (“Orphan Medical”) and assigned to JAZZ PHARMACEUTICALS, INC. (“Jazz Pharmaceuticals”), is entered into as of July 16, 2007 (the “Effective Date”) by and between ESSDS and Jazz Pharmaceuticals. Capitalized terms not otherwise defined herein shall have the same meanings as in the Agreement.

RECITALS

WHEREAS, Jazz Pharmaceuticals desires ESSDS to provide certain Nursing Program Services for its product, Xyrem;

WHEREAS, the parties are discussing ways to enhance the existing Xyrem Success Program, including the possible adoption of a specialty pharmacy HUB program, and ESSDS desires to now hire three additional full time employees in response to these discussions;

WHEREAS, the parties desire to include and describe in more detail the provision by ESSDS of certain Nursing Program Services;

WHEREAS, the parties desire to include and describe in more detail the responsibilities of the three full time employees that ESSDS desires to hire and Jazz Pharmaceuticals’ payment obligation regarding same;

WHEREAS, Section 10.10 of the Agreement provides that the Agreement may be amended by a written instrument signed by both parties; and

WHEREAS, the parties desire to supplement the Agreement as provided herein.

NOW, THEREFORE, in consideration of the foregoing and the respective representations, warranties, covenants and agreements set forth herein and in the Agreement, the parties hereto agree as follows:

AGREEMENT

1. Incorporation of Recitals. The Recitals are hereby incorporated into the Addendum.

2. Definitions. As used in this Addendum, the following term (and the plural thereof, when appropriate) shall have the meaning set forth herein, except where the context makes it clear that such meaning is not intended:

1

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

3. Performance of Nursing Program Services. ESSDS shall perform the Nursing Program Services set forth in Exhibit A for Jazz Pharmaceuticals for its product, Xyrem. ESSDS agrees to perform such Nursing Program Services with due care in accordance with the standards and practices which are generally accepted in the industry and exercised by other persons engaged in performing similar services in the local area and in accordance with all applicable federal and state laws and regulations.

4. Performance of FTE Services. ESSDS will hire a HUB Trainer, a Xyrem Account Director, and a Xyrem Operations Director to perform the FTE Services set forth in Exhibit B for Jazz Pharmaceuticals in connection with the Xyrem Success Program. ESSDS agrees to perform such services with due care in accordance with the standards and practices which are generally accepted in the industry and exercised by other persons engaged in performing similar services in the local area and in accordance with all applicable federal and state laws and regulations.

5. Termination. Either party may terminate this Addendum on thirty (30) days’ prior written notice to the other party, provided, however, that neither party may terminate this Addendum prior to December 31, 2007.

6. Fees. Jazz Pharmaceuticals shall pay ESSDS the monthly fees described in Exhibit C in consideration of the performance of Nursing Program Services and the FTE Services. The fees described on Exhibit C shall constitute full and complete payment for performance of the Nursing Program Services and the FTE Services under the Agreement. Payment of the fees for the FTE Services will commence 30 days following the hire by ESSDS of individuals to perform the FTE Services; payment for the Nursing Program Services will commence on September 1, 2007. ESSDS shall invoice Jazz Pharmaceuticals monthly. Jazz Pharmaceuticals agrees that: (1) the fees for the Xyrem^® Nursing Program Services and the FTE Services shall constitute compensation for bona fide services; (2) the Xyrem^® Nursing Program Services and FTE Services are not intended to serve, either directly or indirectly, as a means of marketing any Jazz Pharmaceutical product, (3) the Xyrem^® Nursing Program and FTE Services are not intended to diminish the objectivity or professional judgment of ESSDS; (4) the Xyrem^® Nursing Program and FTE Services do not involve the counseling or promotion of any off-label use of Jazz Pharmaceutical products; (5) the fees for the Xyrem^® Nursing Program Services and FTE Services are not intended in any way as remuneration for referrals or for other business generated; and (6) any fees for the Xyrem^® Nursing Program Services and FTE Services represent fair market value for these services based

2

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

on arms-length negotiations. The parties acknowledge that fees paid for the Xyrem^® Nursing Program Services and FTE Services pursuant to this Agreement are not intended in any way as a payment related to drug formulary or drug formulary activities and have not been negotiated or discussed between the parties in connection with any such drug formulary or formulary activities.

7. Miscellaneous.

[SIGNATURE PAGE FOLLOWS]

3

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

IN WITNESS WHEREOF, the parties have executed or caused this Addendum to be executed effective as of the Effective Date of this Addendum.

4

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

EXHIBIT A

NURSING PROGRAM SERVICES

Population

Staffing

Contact

The patient may contact the nurse at other intervals throughout the program. Additionally, it may be necessary for the nurse to contact the patient’s physician throughout the program for clarification of orders and/or compliance issues.

Documentation

A-1

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

Reporting

A-2

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

EXHIBIT B

FTE SERVICES

HUB Trainer

The Hub Trainer will provide all training relating to fulfillment and distribution of Xyrem. The Hub Trainer will dedicate [ * ]% of their time to training related to the Xyrem Success Program.

Xyrem Account Director

The Xyrem Account Director will be designed as the single point of contact for Jazz Pharmaceuticals and will be responsible for optimizing the effectiveness of the enhanced Xyrem Success Program. The Xyrem Account Director will dedicate 100% of their time to the Xyrem Success Program.

Xyrem Operations Director

The Xyrem Operations Director will serve as a single point of contact for the Xyrem Account Director. The Xyrem Operations Director will dedicate 100% of their time to the Xyrem Success Program.

All references above to the Xyrem Success Program include any enhancements subsequently made to that program, including adoption of a specialty pharmacy Hub program.

B-1

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

EXHIBIT C

FEES

The fee schedule listed above is subject to the following qualifications:

C-1

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

EXHIBIT D

MONTHLY REPORTS

D-1

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

If patient indicates they are no longer taking Xyrem during one of the above scheduled nurse calls, the nurse will contact the physicians’ office in a timely manner and alert them to this finding.

Glossary of Call Type Codes:

Monthly Number of Calls Reporting Format:

D-2

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

Nurse Opt Out Data Reporting Format

Monthly Nursing Summary Reporting Format:

Nursing Summary

D-3

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.

D-4

[ * ] = Certain confidential information contained in this document, marked by brackets, has been omitted and filed separately with the Securities and Exchange Commission pursuant to Rule 24B-2 of the Securities Exchange Act of 1934, as amended.