A case of accidental neonatal paracetamol overdose with prolonged half-life and measured metabolites

Acetaminophen for the patent ductus arteriosus: has safety been adequately demonstrated?

Patent ductus arteriosus (PDA) is the most common cardiovascular condition diagnosed in premature infants. Acetaminophen was first proposed as a potential treatment for PDA in 2011. Since that time acetaminophen use among extremely preterm neonates has increased substantially. The limited available data demonstrate that acetaminophen reduces PDA without evident hepatotoxicity. These findings have led some to suggest that acetaminophen is a safe and effective therapy for PDA closure. However, the lack of apparent hepatoxicity is predictable. Acetaminophen induced cellular injury is due to CYP2E1 derived metabolites; and hepatocyte CYP2E1 expression is low in the fetal and neonatal period. Here, we review preclinical and clinical data that support the hypothesis that the lung, which expresses high levels of CYP2E1 during fetal and early postnatal development, may be particularly susceptible to acetaminophen induced toxicity. Despite these emerging data, the true potential pulmonary risks and benefits of acetaminophen for PDA closure are largely unknown. The available clinical studies in are marked by significant weakness including low sample sizes and minimal evaluation of extremely preterm infants who are typically at highest risk of pulmonary morbidity. We propose that studies interrogating mechanisms linking developmentally regulated, cell-specific CYP2E1 expression and acetaminophen-induced toxicity as well as robust assessment of pulmonary outcomes in large trials that evaluate the safety and efficacy of acetaminophen in extremely preterm infants are needed.

Racing against time: leveraging preclinical models to understand pulmonary susceptibility to perinatal acetaminophen exposures

Over the past decade, clinicians have increasingly prescribed acetaminophen (APAP) for patients in the neonatal intensive care unit (NICU). Acetaminophen has been shown to reduce postoperative opiate burden, and may provide similar efficacy for closure of the patent ductus arteriosus (PDA) as nonsteroidal anti-inflammatory drugs (NSAIDs). Despite these potential benefits, APAP exposures have spread to increasingly less mature infants, a highly vulnerable population for whom robust pharmacokinetic and pharmacodynamic data for APAP are lacking. Concerningly, preclinical studies suggest that perinatal APAP exposures may result in unanticipated adverse effects that are unique to the developing lung. In this review, we discuss the clinical observations linking APAP exposures to adverse respiratory outcomes and the preclinical data demonstrating a developmental susceptibility to APAP-induced lung injury. We show how clinical observations linking perinatal APAP exposures to pulmonary injury have been taken to the bench to produce important insights into the potential mechanisms underlying these findings. We argue that the available data support a more cautious approach to APAP use in the NICU until large randomized controlled trials provide appropriate safety and efficacy data.

Caffeine disrupts ataxia telangiectasia mutated gene-related pathways and exacerbates acetaminophen toxicity in human fetal immortalized hepatocytes

Preterm infants are at greater risk for adverse drug effects due to hepatic immaturity. Multiple interventions during intensive care increases potential for drug interactions. In this setting, high-dose caffeine used for apnea in premature infants may increase acetaminophen toxicity by inhibiting ataxia telangiectasia mutated (ATM) gene activity during DNA damage response. To define caffeine and acetaminophen interaction, we modeled infantile prematurity in late-gestation fetal stage through human immortalized hepatocytes and liver organoids. The acute toxicity studies included assays for cell viability, mitochondrial dysfunction and ATM pathway-related DNA damage. Fetal cells expressed hepatobiliary properties, albeit with lower metabolic, synthetic and antioxidant functions than more mature hepatocytes. Acetaminophen in IC50 amount of 7.5 millimolar caused significant oxidative stress, mitochondrial membrane potential impairments, and DNA breaks requiring ATM-dependent repair. Caffeine markedly exacerbated acetaminophen toxicity by suppressing ATM activity in otherwise nontoxic 2.5 millimolar amount. Similarly, the specific ATM kinase antagonist, KU-60019, reproduced this deleterious interaction in 5 micromolar amount. Replicative stress from combined acetaminophen and caffeine toxicity depleted cells undergoing DNA synthesis in S phase and activated checkpoints for G0/G1 or G2/M restrictions. Synergistic caffeine and acetaminophen toxicity in liver organoids indicated these consequences should apply in vivo. The antioxidant, N-acetylcysteine, decreased oxidative damage, mitochondrial dysfunction and ATM pathway disruption to mitigate caffeine and acetaminophen toxicity. We concluded that hepatic DNA damage, mitochondrial impairment and growth-arrest after combined caffeine and acetaminophen toxicity will be harmful for premature infants. Whether caffeine and acetaminophen toxicity may alter outcomes in subsequently encountered hepatic disease needs consideration.

N-Acetylcysteine treatment of neonatal acetaminophen toxicity caused by transplacental transfer - a case report

We describe a case of maternal acetaminophen toxicity leading to Caesarean section delivery of a pre-term neonate with acetaminophen-induced hepatic injury and encephalopathy at 33 weeks gestational age. Delayed treatment with N-acetylcysteine (NAC) was initiated in the baby 11 h after delivery, with eventual discharge of a healthy baby at 12 days of age. The baby was treated with a standard but extended duration NAC protocol. Post-operatively, liver biopsy of the mother demonstrated acetaminophen-induced hepatic injury overlying mild hepatic steatosis. This was also managed with NAC therapy leading to complete clinical resolution of acetaminophen induced hepatic injury and discharge on post-operative day 10. This case of delayed NAC therapy for the treatment of pre-term neonatal acetaminophen toxicity is one of very few reported in the literature and can be used as a guide in the management of subsequent cases.

Paracetamol overdose in the newborn and infant: a life-threatening event

PURPOSE

Paracetamol is the only drug recommended to treat fever in neonates. At recommended doses, paracetamol has not been associated with liver injury in neonates, while hepatotoxicity may occur after intake of a single high dose or multiple excessive doses. The aim of this narrative review is to critically analyze and summarize the available literature on newborns and infants exposed to supratherapeutic doses of paracetamol, with special focus on their clinical features, outcome, and management.

METHODS

The PubMed, SCOPUS, and Google Scholar search engines were used to collect data, without time limitation. The following keywords were used: paracetamol/acetaminophen, overdose, hepatotoxicity, N-acetylcysteine, newborn, infant.

RESULTS

The literature search identified a total of 27 case reports, a number of review articles, and few other relevant publications. Neonatal poisoning from paracetamol resulted from transplacental drug transfer after maternal overdose in some published cases, while it was the consequence of medication errors in other cases. Newborns and infants who have received a single overdose and have paracetamol concentrations below the Rumack-Matthew nomogram limits are at low risk of serious hepatic damage, while those who have recently ingested more than one supratherapeutic dose of paracetamol should be managed with caution. The treatment of choice for paracetamol poisoning is N-acetylcysteine, a specific antidote which reduces paracetamol hepatotoxic effects. N-Acetylcysteine should be given according to specific regimens through weight-based dosing tables.

CONCLUSIONS

Caution should be used when paracetamol is administered to the newborn. In the event of an overdose, careful patient monitoring and personalization of post-overdose procedures are recommended.