Aims Two post-authorisation studies assessed the safety and persistence of patients’ use of nalmefene. Methods The START study (EUPAS5678) was a non-interventional, multi-country, prospective, 18-month (8 follow-up visits) cohort study including outpatients initiating nalmefene for the first time. The multi-database retrospective cohort study (MDRC, EUPAS14083) included baseline and follow-up data from German, Swedish and UK healthcare databases. Both studies permitted ‘all comers’ without explicit exclusion criteria; predefined subgroups of interest included the elderly (≥65 years) as well as patients with significant psychiatric and/or somatic comorbidities. Results START study: Overall, the mean duration of nalmefene treatment was 10.3 ± 7.3 months (N = 1348), with 49.0% of patients treated for ≥1 year; frequent reasons for treatment discontinuation were ‘goal reached’ and ‘drug cost’. The most frequently reported adverse drug reactions (ADRs) were nausea (4.7%), dizziness (3.2%) and insomnia (2.0%). ADR rates appeared higher in the elderly subpopulation (18.6% reported ≥1 ADR vs. 12.0% in the total population) but were not higher in the other predefined subgroups. MDRC study: The database follow-up analysis followed 2892 patients over 18 months for whom the duration of nalmefene treatment was between 2 and 3 months and <5% of patients used nalmefene for ≥1 year. Conclusions Despite the inclusion of a wider patient population (e.g. elderly patients and those with relevant co-morbidities), the safety and tolerability profile of nalmefene given in routine practice was consistent with previous clinical studies. The differing rates of persistence beyond 1 year likely reflect the different methodologies and highlight the relevance of psychosocial support at follow-up visits.