1090 Paediatric anti-epileptic drug overdoses across the last decade

Abstract

<h3>Aims</h3> Epilepsy affects 1/150 children.¹ Anti-epileptic drugs (AED) control 2 in 3 patients’ symptoms, yet their narrow therapeutic window means they are important preventable causes of paediatric morbidity.² Few data exist exploring childhood AED toxicity. We aimed to explore characteristics of national childhood AED overdoses across the last decade. <h3>Methods</h3> National Poisons Information Service (NPIS) collects age specific U.K. data on telephone enquiries, stored centrally on the UK Poisons Information Database (UKPID). Variables collected included: age, sex, year, month, enquiry source, enquirer, location, symptoms, drug implicated, exposure type (Acute/sub-acute/acute-on-therapeutic/staggered/chronic), circumstance (Accidental/intentional/therapeutic error/other), and Maximum Poisoning Severity Score (MAXPSS). Data was explored for enquiries between 2011 and 2020 for the following AEDs: Carbamazepine, lamotrigine, levetiracetam, sodium valproate, phenytoin, phenobarbital, clobazam, clonazepam, gabapentin, topiramate, ethosuximide, oxcarbazepine. We do not have outcome data/death rates after overdose as this information is not collected by NPIS or Toxbase. Non-Telephone enquiries are not recorded by paediatric age groups and thus not included. <h3>Results</h3> 1,508 enquiries included 706 boys (46.80%), 802 girls (53.2%) with a mean age of 7.58yrs (SD=5.67). Age was bimodally distributed, with highest frequency at 3 and 15 years. Telephone enquiries steadily decreased from 195/yr in 2011 to 128/yr in 2020 (table 1) whilst the number of Internet NPIS TOXBASE searches rose over this time. Most overdoses (n=1376, 91.3%) happened at home, 666 (44.2%) enquiries were made at hospital and 861 (57.1%) were made by a doctor. Most poisonings were accidental (n=593, 39.3%), followed by therapeutic error (n=552, 36.6%) and then intentional overdoses (n=314, 20.8%). Sodium valproate was most commonly implicated (n=351, 22.6%). Carbamazepine enquiries were the most frequently symptomatic (n=156/325, 48.0%), requiring intervention (n=213/325, 65.5%) and scoring above zero on MAXPSS (n=176/325, 54.2%). Overall, 429 enquiries (28.5%) were symptomatic with 593 (38.1%) requiring intervention. Intentional overdoses (n=314) were more likely to be symptomatic (69.1%) and require intervention (78.3%). A higher proportion of interventional poisonings were female patients (80 Male:234 Female). A third of all exposures (n=513, 34.08%) scored above zero out of three on the MAXPSS, with 20.3% (n=306) scoring one, 7.1% (n=107) scoring two and only 4.6% (n=69) scoring three. <h3>Conclusion</h3> AED overdoses are more common in young children (2-3yrs) and teenagers (14-16yrs). In young children it is normally accidental, in teenagers intentional. Carbamazepine was more frequently implicated in severe toxicities. Those taking intentional overdoses are more likely to be female, symptomatic and require intervention. There is still a concerning rate of AED overdoses in UK children resulting in potential harm, hospital admission and treatment. <h3>References</h3> Choonara I. <i>Anti-epileptic drug toxicity in children</i>. Multidisciplinary Digital Publishing Institute; 2018. Sankaraneni R, Lachhwani D. Antiepileptic drugs—a review. <i>Pediatric Annals.</i> 2015;<b>44</b>(2):e36-e42.