The objective of this trial is to evaluate the safety and efficacy of Xyrem® compared to placebo for the treatment of fibromyalgia in a randomized, double blind, placebo controlled, parallel group trial.

The trial is a randomized, double blind, placebo controlled, parallel group trial in subjects diagnosed with fibromyalgia in accordance with the American College of Rheumatology. Total duration is up to twenty-two (22) weeks of trial participation. Subjects will undergo a screening and withdrawal/washout period lasting up to five (5) weeks combined followed by baseline period lasting one (1) week. Total treatment duration will be fourteen (14) weeks followed by a two week safety follow-up post treatment period. During the screening and withdrawal/washout period, no study medication will be given; however rescue medication up to 4 grams per day of acetaminophen (paracetemol) will be allowed.

Inclusion Criteria:

• Male or female subjects, 18 years or older who meet the American College of Rheumatology (ACR) diagnostic criteria for fibromyalgia.

Exclusion Criteria:

• Subjects will be excluded if they have a history of rheumatic disease or other disorders that may compromise reliable representation of subjective symptoms.
• Any other condition that will cause a risk to subjects if they participate in the trial is also a reason for exclusion.