The primary purpose of the study is to evaluate the long term efficacy of sodium oxybate (Xyrem®) and zolpidem tartrate (Ambien®) in treating chronic insomnia. We will compare the efficacy of sodium oxybate with zolpidem tartrate (Ambien®), and compare the efficacy of each of these two medications with placebos.
Primary aim: 1\. To assess the long term efficacy of sodium oxybate and zolpidem tartrate in reducing insomnia and improving sleep quality as assessed by a range of self-reported measures. Questionnaires and Rating Scales: Subjects completed the following questionnaires and scales: Insomnia Severity Index, Epworth Sleepiness Scale (ESS), Beck Depression Inventory, Pittsburgh Sleep Quality Index (PSQI), Profile of Mood States-Fatigue (POMS). These questionnaires were administered at study baseline, treatment week 4, 8 and 12. Clinical Global Impression (CGI). The CGI is a clinician-rated scale composed of two subscales that measure disease severity and degree of change, respectively. CGI-Severity (CGI-S) is a single-item, global scale of disease severity that requires the investigator to compare the patient's symptoms with those of all other patients who have the disorder. It is scored from 1 (normal) to 6 (among the most extremely ill of patients). CGI-Change (CGI-C) is a single-item scale of symptomatic improvement or worsening that requires the investigator to compare the patient's status at the time of assessment with baseline severity (baseline CGI-S). One study investigator performed all CGI-S and CGI-C ratings for all subjects. Randomization. After completing all baseline procedures, eligible subjects were randomized to receive either a combination of active SXB and placebo ZOL (pZOL), active ZOL and placebo SXB (pSXB), or pSXB and pZOL, in a 1:1:1 parallel double-dummy design. A member of the study team who had no contact with subjects and no other role in this study was responsible for preparing study medications according to a randomization schedule. ZOL was encapsulated in lactose powder filled gelatin capsules to be indistinguishable from placebo capsules. Liquid pSXB was designed to match active SXB in appearance, taste and consistency. Subjects were given both liquid and capsule study medications, to maintain the double dummy design. Due to the flexible dose design of this study, subjects and investigators were not blinded to the dosages of study medication/placebo. All subjects were instructed to start study medication at 2.25 grams of SXB/pSXB and 5mg of ZOL/pZOL at bedtime. One study investigator reviewed all potential known side effects of SXB and ZOL prior to dosing, and subjects were instructed to take study medications at the bedside immediately before attempting to sleep, as is the standard administration for SXB.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
48
Stanford University School of Medicine
Stanford, California, United States
Assessment of Clinical Global Impression-change.
Clinician assessment of Clinical Global Impression-Change score at week 12 of treatment intervention. The Clinical Global Impression - Change scale is a 7 point scale that requires the clinician to assess how much the patient's illness has improved or worsened relative to a baseline state at the current time point. It is rated as: 1, very much improved; 2, much improved; 3, minimally improved; 4, no change; 5, minimally worse; 6, much worse; or 7, very much worse. One one clinician provided the ratings in this trial.
Time frame: Baseline to week 12
Assessment of Insomnia Severity Index
Current self-report on Insomnia Severity Index at week 12 of treatment intervention. This is a seven-item questionnaire where the sum of the answers indicate the severity of insomnia. Total score categories: 0-7 = No clinically significant insomnia 8-14 = Subthreshold insomnia 15-21 = Clinical insomnia (moderate severity) 22-28 = Clinical insomnia (severe)
Time frame: 12 weeks
Assessment of Pittsburgh Sleep Quality Index (PSQI)
Current self-report on Pittsburgh Sleep Quality Index (PSQI) at week 12 of intervention. Consisting of 19 items, the PSQI measures several different aspects of sleep which can be combined into one global score. Each item measure is scored on a scale of 0 to 3 where 3 is the extreme negative. The composite PSQI score is then calculated by totaling the seven component scores, providing an overall score ranging from 0 to 21, where lower scores denote a healthier sleep quality. Based on this questionnaire, a composite score of 5 or greater is indicative of poor sleep quality.
Time frame: One month
Assessment of Fatigue
Current self-report on Profile of Mood State -- Fatigue (POMS-F) at week 12 of intervention. This subscale of the POMS consists of 7 items each scored on a scale of 0 (not at all) to 4 (extremely) which are summed to provide a composite score of fatigue. The range is 0 to 28 for this subscale. Higher scores indicate more fatigue.
Time frame: One month
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Assessment of Sleepiness
Current self-report on Epworth Sleepiness Scale (ESS) at week 12 of intervention. This measure consists of 8 scenarios in which the participant is asked to assess how likely s/he is to fall asleep. Scale: 0 = would never doze; 1 = slight chance of dozing; 2 = moderate chance of dozing; 3 = high chance of dozing. Responses are summed for a total score ranging from 0 to 24. The higher the score, the greater the self-reported sleepiness. Scores of 9 and below are considered in the normal range.
Time frame: One month