13
Neonatal Abstinence Syndrome
Neonatal drug withdrawal or neonatal abstinence syndrome (NAS) is often a long a painful process that requires time in the neonatal intensive care unit (NICU). Drug withdrawal occurs as the body removes addictive substances from the circulation. It is characterized by central nervous system (CNS) hyperirritability, gastrointestinal dysfunction, respiratory distress, sleep disturbances, and autonomic instability (Finnegan & Kaltenbach, 1992). Untreated NAS can cause significant morbidity and mortality (Finnegan & Kaltenbach, 1992).
NAS may be caused by fetal exposure and dependence in utero or may be iatrogenic (a result of the use of intensive opioid therapy given to the neonate for pain management).
NAS is not new, it has been studied in many forms and is still very common, especially among industrialized nations. Research in 2004 found that 12 out of 1,000 pregnant women used nonprescription drugs and 75 of 1,000 women reported prescription use of analgesics (Wilbourne, Wallerstedt, Dorato, & Curet, 2001). Critically ill patients in the NICU can also experience primary withdrawal from pain medications. Babies may be given consistent morphine or fentanyl because of their diagnosis or perioperatively and then need to be slowly withdrawn from this medication, possibly resulting in NAS symptoms.
Major drugs of abuse include opioids, CNS stimulants, CNS depressants, and hallucinogens, all of which can cause NAS symptoms in the newborn. These symptoms include neurological excitability such as irritability and inability to sleep as well as gastrointestinal effects such as uncoordinated or constant suck, diarrhea, and vomiting (Hudak, Tan, Committee on Drugs, Committee on Fetus and Newborn, & American Academy of Pediatrics, 2012). In a sample of women presenting for drug treatment during pregnancy, more than 89% of neonates experienced NAS that required pharmacological treatment (Woods, 1996).
Iatrogenic withdrawal symptoms have been documented in infants on fentanyl or morphine intravenous drips to maintain continuous analgesia during such therapies as extracorporeal membrane oxygenation (ECMO) and mechanical ventilation (Tobias, 2000).
There are many nonnarcotic drugs that may cause withdrawal symptoms with fetal exposure. Alcohol, barbiturates, caffeine, chlordiazepoxide, clomipramine, diazepam, ethchlorvynol, glutethimide, hydroxyzine, meprobamate, and selective serotonin reuptake inhibitors (SSRIs) are examples (Hudak et al., 2012).
Exposure to drugs during pregnancy has been shown to cause many complications, such as miscarriage, preterm labor, placental abruption, postpartum hemorrhage, malnutrition, anemia, and infections (urinary tract infections or infections often associated with drug abuse such as sexually transmitted diseases). Fetal complications can include intrauterine growth restriction; preterm birth; low birth weight; congenital anomalies; NAS; sudden infant death syndrome; increased incidence of respiratory, ear, and sinus infections; as well as neurologic and behavioral disorders (Behnke, Smith, Committee on Substance Abuse, & Committee on Fetus and Newborn, 2013; Narkowicz, Plotka, Polkowska, Bizuik, & Namiesnick, 2013).
Premature infants may have less severe NAS symptoms compared to term infants. In a study, lower gestational age equated to a lower risk of withdrawal with less severe symptoms when mothers received the same dose of methadone (Liu, Jones, Murray, Cook, & Nanan, 2010). The decrease may be related to a less mature CNS and less fat storage of the drug. This does not mean that the preterm baby will not need treatment. A standardized scale should be used for all babies and treatment given if needed.
Treatment for NAS includes the use of drug therapy to relieve moderate to severe symptoms of withdrawal (Hudak et al., 2012). Therapy varies with institutional guidelines and provider decision. See Table 13.1 for things to consider when NAS is suspected.
The most common treatments for NAS include opioids (tincture or opium, neonatal morphine, methadone, and paregoric) but barbiturates (phenobarbital), benzodiazepines (diazepam and lorazepam), clonidine, and phenothiazines (chlorpromazine) are often added to the treatment regimen—see Table 13.2 for sample dosages (Hudak et al., 2012). Treatment is usually dependent on careful scoring using a validated NAS scale, such as the Finnegan NAS scale, which is shown in Figure 13.1.
TABLE 13.1 Factors to Consider When NAS Is Suspected
1. What do the results of drug screening show? (Maternal urine, neonatal urine, and neonatal meconium) |
2. Does the baby have symptoms? |
3. What is the severity of the symptoms according to a tested scale approved by the institution? (Symptoms need to be rechecked frequently according to the guidelines of the scale.) |
4. If treatment has begun, is it effective? |
5. Can the treatment be weaned? (Again, this is according to institutional policy for weaning. The aim should be to give the least amount of drug that is still effectively assisting with the withdrawal process.) |
6. Are social services involved? |
7. Is the guardian of this baby involved? (The biological or foster parents should be involved in care as soon as possible. This will both create a smoother transition for discharge and help with the weaning process as they will be able to help with nonpharmacological pain-relief measures.) |
NAS, neonatal abstinence syndrome.
TABLE 13.2 Common Treatment Doses for NAS
Morphine |
Initial dose: 0.08 mg/kg every 3–4 hr |
Titration: Increase by 0.04 mg/kg/dose |
Maximum dose: 0.2 mg/kg/dose |
Methadone |
Initial dose: 0.05–0.1 mg/kg every 6 hr |
Tincture of opium |
1 mL is added to 24 mL of sterile water to make a concentration equal to that of 0.4 mg of morphine |
Initial dose: 0.4 mg by mouth in 6–8 divided doses |
Titration: Dose should be increased by 0.04 mg/kg/d or 0.1 mL |
Phenobarbital |
Initial dose: 20 mg/kg to achieve therapeutic level in one dose |
Titration: 10 mg/kg every 12 hr until control or toxicity is noticed |
Maintenance dose: 2–6 mg/kg/d for 3–4 day; decrease dose to 3 mg/kg/day |
Clonidine |
Dose: 0.5–1 mcg/kg every 3 hr with a maximum dose of 1 mcg/kg every 3 hr |
NAS, neonatal abstinence syndrome.
Sources: Gardner, Carter, Enzman-Hines, and Hernandez (2011) and Hudak et al. (2012).
FIGURE 13.1. Finnegan’s NAS scale.
NAS, neonatal abstinence syndrome.
Source: Finnegan (1988). Copyright © Elsevier.
REFERENCES
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