Inclusion Criteria:

   - Inborn and outborn infants of 29 0/7 to 33 6/7 weeks gestational age at birth

   - admitted to hospitals of the NICHD NRN who, are at time of enrollment:

   - ≤35 6/7 weeks post-menstrual age at the time of randomization

   - Receiving caffeine with plan to discontinue treatment or just discontinued caffeine
   treatment

   - Receiving feeds at a volume of ≥120 ml/kg/day by oral and/or tube feeding

   - Ability to start study medication within 72 hours after stopping caffeine

Exclusion Criteria:

   - On respiratory therapy (oxygen more than room air equivalent for high altitude sites,
   nasal cannula, continuous positive pressure ventilation, and/or mechanical
   ventilation)

   - Infants who would otherwise be discharged home on apnea monitor due to underlying
   disease or family history, including history of a sibling with sudden infant death
   syndrome

   - Parental request for apnea monitor

   - Congenital heart disease other than atrial septal defect, ventricular septal defect,
   or patent ductus arteriosus

   - Neuromuscular conditions affecting respiration

   - Major congenital malformation and/or genetic disorder

   - Plans to transfer to a non-NRN site before discharge

   - Unable to obtain parental or guardian consent