Unspecified opioids among opioid overdoses in Oslo, Norway

Since 2017, an increasing number of opioid overdoses in Oslo, Norway, has been categorized as involving unspecified opioids, as noted in the patient records by the doctor treating the patient. In this study we compare the characteristics of overdoses involving unspecified opioids, long-acting opioids, and heroin. Data on patients presenting with opioid overdose was retrospectively collected from 1 October 2013 to 31 December 2019 at the Oslo Accident and Emergency Outpatient Clinic. Among 2381 included cases, 459 (19.3%) involved unspecified opioids, 134 (5.6%) long-acting opioids, and 1788 (75.1%) heroin. Overdoses involving unspecified opioids needed longer observation, median 5 h 29 min vs. 4 h 54 min (long-acting opioids) and 4 h 49 min (heroin) (p