Methadone toxicity in infants: a report of two fatalities

Abstract

Fatalities in infants resulting from methadone toxicity are rare within the United Kingdom. We report two cases of fatality attributed to methadone toxicity in infants aged 3(1/2) and 15 months of age, respectively. One of the two cases was also associated with diazepam ingestion. We discuss the difficulties with the interpretation of paediatric forensic toxicology and review the current literature related to methadone and diazepam toxicity in infants and older children.

The Toxicology of Methadone‐Related Death in Infants Under 1 Year: Three Case Series and Review of the Literature

“…The blood methadone levels in our cases were 69, 440, and 190 ng/mL which fall within the previously reported methadone levels by Mistry et al in methadone‐related fatalities in young children ranging from 60 to 1100 ng/mL. Fatal blood concentration of methadone in infants <1 year in the literature inclusive of our three cases ranges from 69 to 700 ng/mL (Table ).…”

“…The interpretation of pediatric postmortem toxicology relies on the literature published on adults; however, infants have crucial physiological differences that may impact analysis and interpretation . Methadone is cleared by cytochrome P450‐mixed oxidase (CYP3A, CYP2B6, CYP2D6 enzyme systems), all of which are immature at birth .…”

“…In the context of infant toxicology, reports of pediatric methadone ingestion have been published since the late 1960s . Methadone‐related death in infants <1 year is rare with only five previously reported cases in the literature . With the growing usage of methadone in adults, the number of poison exposure cases in infants is increasing .…”

“…Despite the certainty in forensic methadone poisoning in older age groups, methadone‐related death in infants is more difficult to decipher due to the variations in pediatric toxicology and the lack of neonate‐specific data. This may contribute to these cases being labeled as undetermined by the forensic community . This case series discusses the difficulty in interpretation of toxicological findings in infants and importance of thorough investigative history, laboratory, and autopsy findings to establish a manner of death in methadone‐related infant deaths.…”

Ingestion accidentelle de méthadone chez un enfant de 11 mois

“…La concentration maximale par gélule de « méthadone sèche » est de 40 mg. Il existe cependant dans les pays limitrophes (en Belgique notamment) un risque d'exposition à des prépara-tions magistrales nettement plus dosées (plus de 100 mg par gélule) pouvant mettre particulièrement en danger une population pédiatrique [1]. Les intoxications accidentelles chez les enfants de moins d'un an restent exceptionnelles [2][3][4][5].…”