Orphan Medical Announces Acceptance of Xyrem (Sodium Oxybate) Oral Solution Filing in Europe

Minneapolis, MN - March 31, 2004

Orphan Medical, Inc. announced today that Celltech Pharmaceuticals, a division of Celltech Group plc received notice that the European Medicines Evaluation Agency (EMEA) has accepted for review its marketing authorization application for Xyrem® (sodium oxybate) oral solution, a treatment for symptoms of narcolepsy.

Xyrem has been filed through the EU centralized procedure, and has been granted Orphan Drug designation status in Europe, which provides a 10-year period of marketing exclusivity upon approval. Celltech will use its specialist sales forces to market the product to neurologists and sleep specialists across Europe following approval, anticipated during 2005.

Celltech licensed the European rights to Xyrem from Orphan Medical in October 2003. Under the terms of the agreement, Celltech will be responsible for the registration, sales and marketing of Xyrem in Europe. Celltech made a milestone payment to Orphan Medical related to the European regulatory filing and will make further payments tied to future product development milestones and sales related milestones. Celltech will also pay Orphan a royalty on sales of the product. The licensing agreement also provides Celltech with rights to negotiate in regard to other potential future indications including fibromyalgia syndrome.

"The filing of this application for approval, which came about very quickly thanks to the efforts of those at Celltech and our internal staff, is the first important step in establishing a worldwide brand for Xyrem," said John Bullion, Orphan Medical CEO.

Ingelise Saunders, Celltech's Global Commercial Director, commented: "We are pleased at having rapidly submitted our marketing authorization application for Xyrem in narcolepsy, in line with our expectations. Xyrem will be an important product within our European specialist-focused commercial organization. We are looking forward to progressing our European submission and working with sleep centres and physicians in order help fulfill the unmet medical need in patients with this serious disorder."

Narcolepsy is a chronic, debilitating neurological disease. Cataplexy associated with narcolepsy, a sudden loss of muscle tone, is usually triggered by strong emotions such as laughter, anger, or surprise. As such, patients often selectively isolate themselves from interaction with others resulting in a dramatic effect on a patient's quality of life. Xyrem is the first and only approved medication for the treatment of cataplexy. Narcolepsy afflicts approximately 100,000 to 140,000 Americans with about 50,000 to 75,000 patients receiving some form of treatment for their symptoms. An estimated sixty to ninety percent of those with narcolepsy suffer from cataplexy.

Orphan Medical acquires, develops, and markets pharmaceuticals of high medical value for inadequately treated and uncommon CNS diseases treated by specialist physicians. The lead product for the company is Xyrem, which is the first and only approved treatment for cataplexy associated with narcolepsy. Xyrem is also being assessed as a treatment for the full range of narcolepsy symptoms including excessive daytime sleepiness. Orphan Medical's pipeline includes development stage products for fibromyalgia and pain. Orphan Medical's Internet Web site address is www.orphan.com

The information in this press release may contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. A number of factors could cause actual results to differ materially from the Company's assumptions and expectations. These are set forth in the cautionary statements included in Orphan Medical's most recent Form 10-Q or Form 10-K filed with the Securities and Exchange Commission. (These documents can be accessed through the Orphan Medical Web site at http://www.orphan.com ). All forward-looking statements are qualified by, and should be considered in conjunction with, such cautionary statements.