BASINGSTOKE, England - (23 May, 2002) - Shire Pharmaceuticals Group plc (LSE: SHP, Nasdaq: SHPGY, TSX: SHQ) announces that it has received Food and Drug Administration (FDA) approval for three further strengths of ADDERALL XR(TM) (mixed salts of a single entity amphetamine product), its once a day treatment for Attention Deficit Hyperactivity Disorder (ADHD).

   The newly approved 5, 15 and 25mg capsules complement the existing 10, 20 and 30mg capsules to provide doctors with significant flexibility to individually tailor the dosing to each patient's needs. With this wider range now available patients converting from ADDERALL(TM) to ADDERALL XR will be able to change more easily from their existing daily dose of ADDERALL directly to the convenient and effective once a day ADDERALL XR capsule.

   Bill Nuerge, President and CEO, Shire US Inc. said: "The availability of a full complement of strengths for ADDERALL XR furthers our goal to provide doctors and their ADHD patients with effective treatments that suit their needs and lifestyles. We have continuous commitments to a long-term presence in this important expanding disease area which includes work to extend the indications for ADDERAL XR together with developing new non-scheduled ADHD treatments."

Notes to editors
Shire Pharmaceuticals Group plc

   Shire Pharmaceuticals Group plc (Shire) is a rapidly growing international specialty pharmaceutical company with a strategic focus on three therapeutic areas -- central nervous system disorders (CNS), oncology and anti-infectives. Shire also has two platform technologies: advanced drug delivery and Biologics. Shire's core strategy is based on research and development combined with in-licensing and a focus on eight key pharmaceutical markets.

For further information on Shire, please visit the company's website: http://www.shire.com

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   THE "SAFE HARBOR" STATEMENT UNDER THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995. The statements in this press release that are not historical facts are forward-looking statements that involve risks and uncertainties, including but not limited to, risks associated with the inherent uncertainty of pharmaceutical research, product development and commercialization, the impact of competitive products, patents, and other risks and uncertainties, including those detailed from time to time in periodic reports, including the F-4 Prospectus and the Annual Report filed on Form 20-F with the Securities and Exchange Commission.