• Pain intensity and pain interference subscales from the Brief Pain Inventory (Short-form) (BPI) will be used to measure pain over the interval following surgery. [ Time Frame: at the clinical follow-up appointment approximately 7-10 days after surgery ] [ Designated as safety issue: No ]
  

• Pain severity will be assessed daily following surgery with a visual analogue scale (VAS) completed by participants each night before they go to bed (daily diary PM). [ Time Frame: each of the days following surgery until the clinical follow-up appointment ] [ Designated as safety issue: No ]
  
• Analgesic medication consumption will be calculated (morphine equivalency) on a daily basis using data down loaded from the PCA pump supplemented by information from clinical charts and patient self report on the daily diary form. [ Time Frame: daily from the day of surgery until the clinical follow-up appointment ] [ Designated as safety issue: No ]
  

Despite continuing improvements in surgical procedures and ancillary care, post surgery pain continues to be a nearly universal patient experience following major operative procedures. Opioids provide considerable pain relief, but they have multiple adverse side effects and are not entirely effective. For cancer patients, uncontrolled postoperative pain can have a substantial negative effect on quality of life, can slow recovery, increase the likelihood of complications, and contribute to poorer postoperative outcomes. The identification of novel modifiable patient risk factors for post surgery pain that could become the target of presurgery interventions is thus an important goal. We will conduct a randomized, placebo-controlled, double-blind intervention trial design to evaluate the effects of an FDA approved hypnotic (zolpidem) on post surgery pain. Since presurgery psychological factors (e.g., heightened anxiety) are known to predict the severity of post surgical pain and may be associated with poor sleep, we will also assess psychological factors (with questionnaires) as well as sleep (using actigraphy) in order to determine their individual and combined impact on women's experiences of post surgery pain in this stressful clinical context. Aim 1: To determine the impact of zolpidem administered the night prior to endometrial cancer surgery on women's experiences of pain over the initial 7-10 day follow-up period after surgery using a double-blind placebo-controlled design (final n=128). Aim 2: To investigate psychological factors on the morning before surgery, as well as objective sleep variables on the night before surgery, as possible mediators of the beneficial effects of zolpidem on post surgery pain. Aim 3: To examine psychological factors, as well as sleep variables, assessed prior to the sleep intervention as possible moderators of the ameliorative effects of zolpidem on post surgery pain. The results of the proposed exploratory study would provide the preliminary data necessary for an R01 application to support more comprehensive investigations, including explorations of biological mechanisms underlying the preventative effects of better presurgery sleep on patients' experiences of post surgery pain.