Characteristics and risk factors of opioid poisoning in opioid-dependent individuals using their primary opioid of dependence: a registry-based study.

Opioid addiction and poisoning are prevalent health issues in Iran, where various types of opioids are easily accessible. Despite being dependent on a specific type of opioid, some opioid-dependents abuse different types opioids which can prone them to some consequences. This study aimed to assess the characteristics and risk factors of opioid poisoning among opioid-dependent individuals poisoned by their own or opioid. This cross-sectional study analyzed data from the MTR-MUMS-Iran (May 2021-January 2022), including opioid-dependent adults poisoned by their regularly used opioid. Opioid dependency was categorized as synthetic opioid or opiate. Data extracted included demographics, opioid type, manner of poisoning, and clinical manifestations. Also, a comparison was conducted between poisoning prevalence with 2011 Iranian Mental Health Survey (IMHS) opioid dependency data. Among 3064 registered cases, 116 patients with a mean age of 40.27 years were included, with a mortality rate of 1.7% (n = 2). The frequency of synthetic opioid and opiate overdose was similar (50.9% vs. 49.1%). Opium and methadone were the most common opioids involved. The most common clinical presentation was decreased level of consciousness (72.4%). Excessive use (50.9%), suicide (24.1%), were the main scenarios leading to poisoning. The manner of poisoning among elderly and opiate-dependent patients was excessive use, while younger synthetic opioid-dependent patients tended to attempt suicide. Furthermore, opiate-dependent individuals were more likely to co-ingest therapeutic medications and have underlying renal disease. The average hospital stay was 2.31 days, with age being a significant predictor of length of stay. The findings of this study suggest some practical implications for physicians. Excessive use and suicide are the two main manners of opioid poisoning among opioid dependents. Women and methadone-dependent cases are at higher risk for opioid toxicity, and buprenorphine appears to be the safest opioid option. © 2025. The Author(s).