The Relationship Between Naldemedine Administration and the Maximum Dose of Oral Opioids

818 Background: Opioid-induced constipation (OIC) is the most common side effect of opioid therapy. Laxatives are usually used as a first-line treatment for OIC. Treatment options for OIC are switching to other opioids associated with less frequent OIC, such as Fentanyl. Naldemedine is an orally active peripherally acting µ-opioid receptor antagonists that was approved in Japan from 2017 for management of cancer-related OIC. The aim of this study is to investigate the relationship between Naldemedine administration and the maximum dose of oral Oxycodone which is the most frequently used oral opioids at our hospital. Methods: During June 2017 and December 2018, a total of 217 patients with cancer-related pain received Oxycodone at our institution. The first group of the patients concurrently received Naldemedine 0.2 mg daily (group A, n = 101), and the second group didn’t receive it (group B, n = 116) for cancer-related OIC reduction. We compared the maximum Oxycodone dose between two groups by medical record retrospectively. Results: The median age of group A was 69 y.o. (range 20-87 y.o.), and the median age of group B was 67 y.o. (range 27-88y.o.). There was no significant difference in common patient background between group A and B. The median dose of maximum Oxycodone dose of group A was 40 mg/day (range 10-480 mg/day), and that of group B was 20 mg/day (range 10-320 mg/day). There was a significant difference in the median dose of maximum Oxycodone between group A and B (Mann-Whitney U test, P < 0.0001). In Group A, the administration was started in 31 patient Naldemedine and Oxycodone at the same time. As for 70 remaining patients, the administration was started when they had constipation after oxycodone was administrated. In those patients, the median days was 19 days from the Oxycodone administration starting date to the Naldemedine administration starting date. Conclusions: Naldemedine administration in patients with cancer-related OIC may increase the maximum dose of oral Oxycodone.