Effects Of Methadone Exposure Research Articles

Methadone and neonatal abstinence syndrome (NAS): what we think we know, but do not.

Since the first use of methadone to treat OUD in pregnancy in the 1970s, there has been a long, controversial, and confusing history of studies, regulatory actions, and practice changes that have clouded an accurate perception of methadone's use in pregnancy. This review will trace this history with a focus on the effect of methadone exposure during pregnancy on neonatal abstinence syndrome (NAS). A new laboratory measure, the serum methadone/metabolite ratio (MMR), has provided a tool for documenting the profoundly dynamic nature of perinatal metabolism. Continuous induction of metabolic enzymes during pregnancy requires dose adjustments and dose frequency changes. The concept of "fetal methadone dosing" emphasizes that relative stability of methadone levels in the fetus is an important consideration for methadone dosing in pregnancy. Finally, the effects of the societal "war on drugs" on pediatric management of neonatal withdrawal risks will be discussed, as well as the importance of comprehensive services for mother and child including the "rooming-in" approach of neonatal care which has considerably replaced the older NICU care model of maternal/infant separation.

Methadone administered to rat dams during pregnancy and lactation affects the circadian rhythms of their pups.

The circadian clock is one of the most important homeostatic systems regulating the majority of physiological functions. Its proper development contributes significantly to the maintenance of health in adulthood. Methadone is recommended for the treatment of opioid use disorders during pregnancy, increasing the number of children prenatally exposed to long-acting opioids. Although early-life opioid exposure has been studied for a number of behavioral and physiological changes observed later in life, information on the relationship between the effects of methadone exposure and circadian system development is lacking. Using a rat model, we investigated the effects of prenatal and early postnatal methadone administration on the maturation of the circadian clockwork in the suprachiasmatic nucleus (SCN) and liver, the rhythm of aralkylamine N-acetyltransferase (AA-NAT) activity in the pineal gland, and gene expression in the livers of 20-day-old rats. Our data show that repeated administration of methadone to pregnant and lactating mothers has significant effect on rhythmic gene expression in the SCN and livers and on the rhythm of AA-NAT in the offspring. Similar to previous studies with morphine, the rhythm amplitudes of the clock genes in the SCN and liver were unchanged or enhanced. However, six of seven specific genes in the liver showed significant downregulation of their expression, compared to the controls in at least one experimental group. Importantly, the amplitude of the AA-NAT rhythm was significantly reduced in all methadone-treated groups. As there is a strong correlation with melatonin levels, this result could be of importance for clinical practice.

Effects of Methadone Exposure during Development on Avian Brain and Blood Cells

Maintenance with methadone is standard treatment for opioid-addicted patients, including pregnant women. Cellular effects of methadone exposure during development are investigated by using an avian model, which is free of confounding maternal variables. In the first study, which explored dose by duration interactions, methadone was administered at one of two doses (0.458 mg/kg or 1.75 mg/kg) for one of three durations of exposure: late in development (Incubation Days 12 to 19), middle to late (Days 9 to 19), or early to late (Days 5 to 19). In the second study, 1.00 mg/kg of methadone was administered from days 8 to 18 and compared with controls (0.00 mg/kg). Brain tissue and blood samples were harvested for all dose conditions from the two studies. Increased methadone exposure was associated with subependymal anomalies, subependymal hemorrhaging, edema, monocytic infiltration, an increase in disintegrating red blood cells, an increase in white blood cells, and a decrease in neurons. Significant differences in variance for cell counts by condition were observed. Exposed specimens had significantly more thrombocytes (t = - 2.66, p < 0.05). The anomalies suggest that methadone exposure may be harmful to develop organisms at the cellular level.