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 sustainedrelease 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 sustainedrelease 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. Conclusion 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. Keywords Opioid analgesics . Cancer . Pain