Restriction of non-opioid analgesics sold over-the-counter in Denmark: A national study of impact on poisonings

Objective: Self-poisoning with non-opioid analgesics presents a growing challenge to health care providers. We aimed to assess the impact of an 18-year age restriction of OTC sales and a pack size restriction of non-opioid analgesics sold OTC in pharmacies on hospital-treated poisonings and poisoning severity measured using biomarkers. Methods: We applied a before and after design using interrupted time series analysis. Data on all poisonings recorded as hospital admissions were obtained during 2002–2015 and biochemical parameters from laboratory databases during 2011–2015, both covering the entire Danish population. Results: The age restriction was followed by a 17% level reduction in admissions for non-opioid analgesic poisoning among young people age 10–17 years (RR 0.830; 95% CI 0.697–0.988; p < 0.036). After the pack size restriction, an instant level reduction of 18.5% (RR 0.815; 95% CI 0.729–0.912; p < 0.001) was observed for the entire population. A 27% decrease in the number of poisonings with alanine transaminase levels (ALT) ≥ 210 U/L was observed (RR 0.734; 95% CI 0.579–0.931; p = 0.011) followed by 40% decrease in biomarkers indicative of liver failure (RR 0.597; 95% CI 0.421–0.847; p = 0.004). We also observed similar reductions for other poisonings such as psychotropics. Limitations: Although declines in poisonings were observed after implementation of means restrictive measures, a causal link cannot be inferred. Conclusion: Age and pack size restriction were assiociated with a reduction in the numbers of poisonings. This was also observed for pharmaceutical poisonings in general, which might suggest a non-specific or spill-over effect.