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-one (21) 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 one (1) week safety follow-up post treatment period. During the screening and withdrawal/washout period, no study medication will be given; however rescue medication acetaminophen (up to 4 grams per day) 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.