Analyses of Respiratory Depression Associated with Opioids in Cancer Patients Based on the Japanese Adverse Drug Event Report Database.

Opioid-induced respiratory depression is a potentially life-threatening adverse drug event. The purpose of this study was to evaluate the incidence of respiratory depression using the Japanese Adverse Drug Event Report (JADER) Database to obtain data to promote proper use of opioids. The JADER database from April 2004 to March 2017 was obtained from the Pharmaceuticals and Medical Devices Agency. We calculated the reporting odds ratios (RORs) of suspected opioids (morphine, fentanyl, oxycodone, tapentadol, methadone, tramadol, pentazocine, buprenorphine, and codeine phosphate hydrate), analyzed the daily dose at first appearance and the time-to-onset profile, and assessed the hazard type using the Weibull shape parameter. ROR analysis detected adverse event signals for all opioids. Morphine showed a large ROR value with statistical significance in elderly (≥70 years old) patients. The median daily doses of oral morphine and oxycodone for inducing respiratory depression were comparably low (30 mg/d as oral morphine equivalent dose), while that of transdermal fentanyl was 120 mg/d (oral morphine equivalent dose). On time-to-onset analysis using the Weibull distribution, those opioids were classified as the early failure type. The median time-to-onset of oral morphine, oral oxycodone and transdermal fentanyl was 5.5, 11 and 12.5 d, respectively, and almost 50% of cases were reported within 30 d. Taken together, our results suggest that it is important to monitor patients carefully for at least the first one week to one month, even if opioids are administered at a relatively low dose, especially in elderly patients administered morphine.