Inclusion Criteria

• Sign & date informed consent
• Willing & able to complete trial as described in protocol
• > 18 years of age
• Meet American College of Rheumatology criteria for Fibromyalgia [Widespread pain for at least 3 months, including all of the following: (1) Pain on right & left sides of body; (2) Pain above & below waist; (3) Pain in axial skeleton; 4) Pain on digital palpation with approximately 4kg force in at least 11 of 18 tender point sites]
• (Study continuation) Have an average VAS pain score > 4 on a scale of 0 to 10 as recorded in patient diary the last week before Visit 4.
• Discontinue all prescription medication taken for fibromyalgia, including opiates, benzodiazepines, anticonvulsants taken for pain, antidepressants, cyclobenzaprine (Flexeril), and/or tramadol (Ultram) until study completion
• Continue all pre-existing nutritional and/or exercise regimens and/or behavioral, massage, acupuncture, physical or cognitive therapies on an unchanged, consistent & regular schedule throughout study
• Use only acetaminophen or over-the-counter non-steroidal anti-inflammatory drugs as rescue pain medications & to limit dose to the labeled over-the-counter maximum. Aspirin may only be used as a cardiac protectant; formulations with caffeine are excluded.
• Forego ingestion of alcohol for duration of study.
• Fertile females must use a medically accepted method of birth control (e.g., barrier method with spermicide, oral contraceptive, or abstinence) for duration of trial.

Exclusion Criteria

1. Have any of the following medical conditions:

   • Other rheumatic disease, such as rheumatoid arthritis, osteoarthritis, or systemic lupus erythematosis
   • Uncontrolled hypo- or hyper-thyroidism of any type
   • Unstable cardiovascular, endocrine, neoplastic (excluding localized basal cell carcinoma), gastrointestinal, hematologic, hepatic, immunologic, metabolic, neurological, pulmonary, and/or renal disease which would place patient at risk during trial or compromise objectives outlined in protocol
   • Myocardial infarction within last six months
   • On their screening PSG have an Apnea Index greater than 10 per hour or an Apnea Hypopnea Index greater than 15 per hour. Note: patients with sleep apnea are not excluded if their indices are below these thresholds while sleeping with CPAP and they are compliant with CPAP therapy.
   • Problems that, in the investigator's opinion, would preclude the patient's participation and completion of this trial or compromise reliable representation of subjective symptoms.
   • If a patient will have to discontinue antidepressant medication taken for depression, the investigator must make an evaluation as to any risks from cessation of anti-depressant therapy. If, in the opinion of the investigator, a reasonable risk of resultant patient harm exists, patient is excluded from study participation
   • Current or recent history of substance abuse including alcohol abuse
   • History of seizure disorder, history of head trauma, migraine headaches or intracranial surgery, & are taking anticonvulsants
   • Succinic semialdehyde dehydrogenase deficiency

2. Have taken any of these therapies:

   • gamma-hydroxybutyrate (sodium oxybate) in 30 days prior to signing informed consent
   • any investigational therapy in 30 days prior to signing informed consent
   • ever taken anticonvulsants to treat epilepsy or any other convulsions

3. Unwilling to stop these therapies during course of trial:

   • anticonvulsants prescribed solely for pain
   • all antidepressants
   • medication for sleep

4. Have any of the following clinical laboratory results:

   • Serum creatinine > 2.0 mg/dL
   • TSH < 0.3 μU/mL OR TSH > 6 μU/mL
   • abnormal liver function tests (SGOT [AST] or SGPT [ALT] more than twice the upper limit of normal)
   • elevated serum bilirubin (more than 1.5 times the upper limit of normal)
   • pre-trial ECG with arrhythmia, greater than a first degree AV block
   • positive pregnancy test at any time during trial

5. Have any of the following socio-economic factors:

   • Pending worker's compensation litigation or related other monetary settlements
   • Have an occupation that requires variable shift work or routine night shifts