Journal Article

Neonatal opioid toxicity: opioid withdrawal (abstinence) syndrome with emphasis on pharmacogenomics and respiratory depression

Baldo, Brian A.

2023

Overview

The increasing use of opioids in pregnant women has led to an alarming rise in the number of cases of neonates with drug-induced withdrawal symptoms known as neonatal opioid withdrawal syndrome (NOWS). NOWS is a toxic heterogeneous condition with many neurologic, autonomic, and gastrointestinal symptoms including poor feeding, irritability, tachycardia, hypertension, respiratory defects, tremors, hyperthermia, and weight loss. Paradoxically, for the management of NOWS, low doses of morphine, methadone, or buprenorphine are administered. NOWS is a polygenic disorder supported by studies of genomic variation in opioid-related genes. Single-nucleotide polymorphisms (SNPs) in CYP2B6 are associated with variations in NOWS infant responses to methadone and SNPs in the OPRM1, ABCB1, and COMT genes are associated with need for treatment and length of hospital stay. Epigenetic gene changes showing higher methylation levels in infants and mothers have been associated with more pharmacologic treatment in the case of newborns, and for mothers, longer infant hospital stays. Respiratory disturbances associated with NOWS are not well characterized. Little is known about the effects of opioids on developing neonatal respiratory control and respiratory distress (RD), a potential problem for survival of the neonate. In a rat model to test the effect of maternal opioids on the developing respiratory network and neonatal breathing, maternal-derived methadone increased apneas and lessened RD in neonates at postnatal (P) days P0 and P1. From P3, breathing normalized with age suggesting reorganization of respiratory rhythm-generating circuits at a time when the preBötC becomes the dominant inspiratory rhythm generator. In medullary slices containing the preBötC, maternal opioid treatment plus exposure to exogenous opioids showed respiratory activity was maintained in younger but not older neonates. Thus, maternal opioids blunt centrally controlled respiratory frequency responses to exogenous opioids in an age-dependent manner. In the absence of maternal opioid treatment, exogenous opioids abolished burst frequencies at all ages. Prenatal opioid exposure in children stunts growth rate and development while studies of behavior and cognitive ability reveal poor performances. In adults, high rates of attention deficit disorder, hyperactivity, substance abuse, and poor performances in intelligence and memory tests have been reported.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Adult / Analgesics, Opioid - toxicity / animal models / Animals / Attention deficit hyperactivity disorder / Autonomic nervous system / Biomedical and Life Sciences / Biomedicine / Breathing / Buprenorphine / Child / cognition / Cognitive ability / distress / DNA methylation / Drug abuse / Drug withdrawal / Environmental Health / Epigenetics / Female / fever / Gastrointestinal symptoms / gastrointestinal system / Genes / genetic variation / Health services / Hospitals / Humans / Hypertension / Hyperthermia / Infant / Infant, Newborn / Infants / Methadone / Methadone - adverse effects / methylation / Morphine / Narcotics / Neonatal abstinence syndrome / Neonatal Abstinence Syndrome - complications / Neonatal Abstinence Syndrome - drug therapy / Neonatal Abstinence Syndrome - genetics / Neonates / Nucleotides / Occupational Medicine/Industrial Medicine / Opioid-Related Disorders - complications / Opioid-Related Disorders - drug therapy / Opioid-Related Disorders - genetics / Opioids / Pharmacogenetics / Pharmacogenomics / Pharmacology/Toxicology / Pregnancy / Prenatal experience / Rats / Respiration / Respiratory Insufficiency - chemically induced / Respiratory Insufficiency - genetics / respiratory rate / Review Article / Rhythm / Single-nucleotide polymorphism / substance abuse / Substance Withdrawal Syndrome - complications / Substance Withdrawal Syndrome - drug therapy / Tachycardia / Toxicity / Weight loss