Abstract
IMPORTANCE: Acetaminophen (paracetamol) is among the most widely used pain medications worldwide; while safe within the therapeutic range, intake exceeding 4000 mg/d can lead to hepatotoxicity. Prior evidence suggests that limiting the availability of large quantities of acetaminophen is associated with decreased acetaminophen-related poisonings and mortality; in Switzerland, 500-mg tablets are available over-the-counter (OTC) and, as of October 2003, 1000-mg tablets are available with prescription. OBJECTIVE: To evaluate the association of adding 1000-mg acetaminophen tablets to the Swiss market with utilization and poisonings. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used a quasi-experimental interrupted time series analysis to evaluate 15 790 acetaminophen poison records from January 1, 2000, to December 31, 2018. All calls for acetaminophen-related poisonings identified from the National Swiss Poisons Centre and all sales for oral acetaminophen tablets (prescription and OTC) dispensed between January 2000 and December 2018 were included. EXPOSURE: October 3, 2003 (Q4 2003), was defined as the intervention date, corresponding to the date of market entry for 1000-mg acetaminophen tablets in Switzerland. MAIN OUTCOMES AND MEASURES: The primary outcome was the number of quarterly acetaminophen-related poison calls to the National Poison Centre. Additional outcomes included quarterly sales for acetaminophen and change in poisoning circumstances, stratified by preintervention and postintervention periods and by formulation (ie, 500-mg and 1000-mg tablets). RESULTS: Between 2000 and 2018, 15 790 acetaminophen-related poisoning calls were identified, of which 10 628 (67.3%) were regarding women, and the mean (SD) age of patients was 25.2 (18.2) years. The interrupted time series analysis identified a significant increase in the slope for the number of reported poisonings following the intervention point, particularly for accidental circumstances (z score, -3.62; P < .001). In the preintervention period, 120 of 961 poisonings (15.3%) involved a dose greater than 10 000 mg, while for the postintervention period, 1140 of 5696 (30.6%) had a dose larger than 10 000 mg (P < .001). There was a rapid uptake in 1000-mg acetaminophen sales, while sales of the 500-mg tablet decreased slightly. Since 2012, a mean (SD) of 20.7 million (1.4 million) 1000-mg tablets were dispensed quarterly compared with 2.7 million (0.5 million) 500-mg tablets. CONCLUSIONS AND RELEVANCE: This study found a significant increase in acetaminophen dispensing and acetaminophen-related poisonings in Switzerland following the approval of 1000-mg tablets in 2003. The availability of 1000-mg acetaminophen should be re-evaluated to minimize the potential for accidental poisonings.