title: Determination of ED50of hydromorphone for postoperative analgesia following cesarean delivery.
abstract: BACKGROUND
  Morphine is the most common opioid injected into the intrathecal space for postoperative analgesia following cesarean delivery, but ongoing medication shortages have resulted in limited availability. One proposed morphine alternative is hydromorphone. Studies investigating its use in post-cesarean analgesia are limited. This study was conducted to determine the median effective dose of intrathecal hydromorphone 12h postpartum.
  
  
  METHODS
  Twenty healthy women undergoing elective cesarean delivery were recruited into this study. Hydromorphone doses were determined using the up-down sequential method. The study dose of hydromorphone started at 6μg and was raised or lowered by 2μg depending on the 12-h efficacy of the preceding participant's dose. Pain scores of <3/10 were considered successful and the subsequent patient received a lower dose. Participants received 0.5% bupivacaine 12.5mg, fentanyl 25μg, and the study dose of hydromorphone as a single intrathecal injection.
  
  
  RESULTS
  Ten of 20 participants reported an effective hydromorphone dosage 12h post-injection. The median effective hydromorphone dosage was 4.6μg (95% CI 3.72 to 5.48μg) based on participants' reported visual analog pain scores of <3/10. No significant side effects or adverse outcomes were observed.
  
  
  CONCLUSIONS
  Intrathecal hydromorphone may be an effective alternative to morphine for post-cesarean pain management. The amount of intrathecal hydromorphone necessary to provide analgesia at 12h postoperatively may be significantly lower than doses currently in use. Further research should be performed to identify the optimal dose of intrathecal hydromorphone for post-surgical pain relief.
authors.affiliation: Department of Anesthesiology, Emory University, Atlanta, GA, USA. Electronic address: glynde@emory.edu.
authors.forename: G C
authors.initials: GC
authors.lastname: Lynde
mesh_terms: D000328:Adult; D016362:Analgesia, Obstetrical / Q000379:methods*; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000775:Anesthesia, Spinal / Q000379:methods*; D002585:Cesarean Section; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D004091:Hydromorphone / Q000494:pharmacology*; D010149:Postoperative Pain / Q000188:drug therapy*; D011247:Pregnancy; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D004091:Hydromorphone
keywords: Analgesia; Cesarean delivery; Hydromorphone; Injections; Spinal