Unintentional buprenorphine and methadone poisoning in children: a matched observational study

Objective To compare accidental pediatric poisoning from methadone vs. buprenorphine in terms of clinical indicators and in-hospital morbidity. Methods A matched observational study conducted on children aged <= 12 years admitted to our center between March 2018 and March 2019 with acute poisoning from methadone or buprenorphine. Data were extracted from the electronic patient files of the pediatric methadone poisoning cases, and buprenorphine poisoning cases were followed from ED, during the study period. Cases were compared regarding rates of bradypnea/apnea (primary outcome), the need for antidote therapy and intubation, duration of hospital stay, miosis, loss of consciousness, blood gas analyses, and mortality (secondary outcomes). Results A total of 90 methadone- and 30 buprenorphine-poisoned children were evaluated. Methadone cases had significantly higher rates of apnea (20/90 methadone vs. 0/30 buprenorphine; OR = 17.7, 95% CI 1.1, 302.8; p = 0.047), but there was no group difference in bradypnea (39/90 methadone vs. 10/30 buprenorphine; p = ns). 28 (31%) methadone and 3 buprenorphine (10%) cases had been referred to as fully awake (p = 0.013). Methadone cases required higher median naloxone doses for initial bolus (0.4 vs. 0.02 mg; p = 0.014) and maintenance infusion (14.4 vs. 2.4 mg; p < 0.001). 20 apnea cases (all from the methadone group) had miotic pupils, and miotic pupils were seen in 44 (90%) cases with bradypnea (OR = 3.2, 95% CI 1.1, 9.3; p = 0.026). Intubation was needed in only 5 methadone cases (5.5%; p = ns). All patients survived. Conclusion Compared to children poisoned with methadone, buprenorphine cases had higher rates of loss of consciousness on admission but subsequently experienced fewer complications during hospital treatment, which is likely due to the buprenorphine partial antagonist effect. Our findings suggest that methadone exposure is more toxic than buprenorphine in pediatric populations.