Gabapentin was thought to have low abuse potential, but it is increasingly being abused by people with
substance use disorder in an attempt to potentiate the euphoric effects from
opioids and other
CNS depressants. Additionally, infants co-exposed to
gabapentin and
opioids during pregnancy tend to exhibit prolonged and more severe
neonatal abstinence syndrome. In this study, we describe positivity rates among commonly abused drugs and rates of co-medication with
gabapentin in a large dataset of umbilical cord tissue specimens (n = 25,422) submitted for routine newborn
drug testing at a national clinical reference laboratory (ARUP Laboratories,
Salt Lake City, UT, USA). Detection of prenatal
drug exposure in umbilical cord tissue specimens was accomplished using a semi-quantitative liquid chromatography-tandem mass spectrometry assay designed to detect 47 specific drugs and
drug metabolites including
opioids, stimulants,
sedative-
hypnotics and
hallucinogens. A positive result for at least one of the measured drugs or
drug metabolites was reported in 7,054 (28%) of the umbilical cord tissues analyzed.
Gabapentin had a positivity rate of ~2% with 562 positive results. Of the 562
gabapentin-positive samples, 395 (70%) also had a positive result for at least one other
drug or
drug metabolite, with the highest co-positivity rate observed for
norbuprenorphine (32%, n = 182) followed by
amphetamine (15%, n = 84),
buprenorphine (13%, n = 74),
methamphetamine (12%, n = 68),
morphine (11%, n = 64),
fentanyl (10%, n = 54) and
naloxone (10%, n = 54). Notably, the concentration of
gabapentin in
gabapentin-positive umbilical cord specimens was higher in
buprenorphine-containing specimens as compared to specimens containing other
opioids, stimulants or
benzodiazepines. Identification of neonatal co-exposure to
gabapentin and
opioids, particularly
buprenorphine, may guide clinicians in rapid initiation of monitoring and intervention for
neonatal abstinence syndrome.