Trends in adverse drug reactions related to oral weak opioid analgesics in therapeutic use in adults: A 10-year French vigilances retrospective study

To describe the symptoms, patient demographics, and trends over time of adverse drug reactions (ADRs) related to weak opioid analgesics reported to the French vigilance networks. Retrospective study of data from French Poison Control Centers and Pharmacovigilance Centers databases of weak opioid analgesics-related ADRs cases, with high causality score, in adults, in therapeutic analgesic use, without co-exposure, between 2011 and 2020. The number of cases was 388 in the Poisonings database and 155 in the Pharmacovigilance database; ratio of the number of these cases to all reported cases during the study period was 0.02% and 0.03%, respectively. Tramadol was most often involved (74% and 56.1%, respectively), followed by codeine (26% and 38.7%, respectively). There was no significant variation in the number of cases reported. Cases most often involved young adults (median age: 40 years) and mostly women (76%). Gastrointestinal symptoms were mostly reported (80% and 65%, respectively) as described in the Summary of Products Characteristics. Patterns of ADRs were comparable in both databases, except for codeine-associated acute pancreatitis and anaphylaxis that were reported in the Pharmacovigilance database. No fatality was observed. Severity was more often observed in the Pharmacovigilance database (30%) than in the Poisonings database (moderate toxicity: 7%). ADRs mostly occurred among young women using tramadol, without significant variation in the number of reported cases over time. Serious ADRs were more frequently reported to the Pharmacovigilance database, particularly for codeine. Women seemed to be at greater risk of ADRs.