Neonatal abstinence syndrome is a disease that affects children who were exposed to opioid drugs prior to birth. Commonly used treatments at present include morphine or tincture of opium. Buprenorphine is a drug used in adults to treat narcotic dependence, but has not been used for Neonatal Abstinence Syndrome. This trial is designed to see if the use of sublingual (under the tongue) buprenorphine is able to be used safely and easily in newborns with the neonatal abstinence syndrome. Secondary goals will be to see if treatment with buprenorphine is associated shorter stays in the hospital and fewer days of treatment than the use of standard therapy. Another secondary goal will be to understand buprenorphine concentration in the blood of babies treated with the drug (this is called "pharmacokinetics").

Inclusion Criteria:

• ≥ 37 weeks gestation
• exposure to opiates in utero
• demonstration of signs and symptoms of neonatal abstinence syndrome requiring treatment

Exclusion Criteria:

• major congenital malformations and/or intrauterine growth retardation
• medical illness requiring intensification of medical therapy
• concomitant benzodiazepine or severe alcohol abuse, self-report of regular use of alcohol or of benzodiazepines use in the past 30 days, and/or receipt of benzodiazepines by prescription (as determined by self-report or intake urine) by the mother during pregnancy,
• concomitant use of CYP 3A inhibitors (erythromycin, clarithromycin, ketoconazole, itraconazole, HIV protease inhibitors) or inducers (rifampin, carbamazepine, phenobarbital) prior to initiation of NAS treatment
• seizure activity or other neurologic abnormality
• breast feeding
• inability of mother to give informed consent due to co-morbid psychiatric diagnosis
• hypoglycemia requiring treatment with intravenous glucose