title: The dosing frequency of sustained-release opioids and the prevalence of end-of-dose failure in cancer pain control: a Korean multicenter study.
abstract: BACKGROUND
  End-of-dose failure is commonly observed as therapeutic levels of sustained-release opioids fall. However, little is known about using these medications for cancer pain control. To determine the dosing frequency of sustained-release opioids (morphine, oxycodone, and transdermal fentanyl) and the prevalence of end-of-dose failure in clinical practice, a patient-reported survey was performed.
  
  
  METHODS
  A multicenter survey was conducted in 56 hospitals in Korea between June and November 2008.
  
  
  RESULTS
  The study enrolled 1,097 cancer outpatients who were prescribed oral sustained-release opioids (morphine or oxycodone) or transdermal fentanyl. Of the oral sustained-release opioid patients, 67.0% took oral sustained-release oral opioids twice daily, while 26.2% took them more than twice daily. Of the transdermal fentanyl patients, 88.8% wore the patch for 72 h. Of the enrolled patients, 48.3% experienced worsening pain just before the next sustained-release opioid dose, and 36.8% of these patients took medication earlier than the prescribed dosing schedule. Patients felt that oral sustained-release opioids gave adequate pain control lasting an average of 9.6 h, versus an average of 62.9 h for transdermal fentanyl.
  
  
  CONCLUSIONS
  This survey demonstrated that sustained-release opioids are used by patients in a manner that is inconsistent with standard recommendations. End-of-dose failure is suggested to explain increased dosing frequency, and patients reported that adequate pain relief lasted for less time than was stated in the manufacturers' prescription recommendation.
authors.affiliation: Division of Medical Oncology, Dongguk University Ilsan Hospital, Seoul, South Korea.
authors.forename: Do-Yeun
authors.initials: DY
authors.lastname: Kim
authors.forename: Hong-Suk
authors.initials: HS
authors.lastname: Song
authors.forename: Jin-Seok
authors.initials: JS
authors.lastname: Ahn
authors.forename: Baek-Yeol
authors.initials: BY
authors.lastname: Ryoo
authors.forename: Dong-Bok
authors.initials: DB
authors.lastname: Shin
authors.forename: Chang-Yeol
authors.initials: CY
authors.lastname: Yim
authors.forename: Si-Young
authors.initials: SY
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D003692:Delayed-Action Preparations; D004334:Drug Administration Schedule; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage; D009369:Neoplasms / Q000150:complications* / Q000188:drug therapy*; D010098:Oxycodone / Q000008:administration & dosage; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D010147:Pain Measurement / Q000187:drug effects; D056910:Republic of Korea; D013997:Time Factors; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D009020:Morphine; D010098:Oxycodone; D005283:Fentanyl