Theophylline was an orally administered xanthine used for treatment of apnea of prematurity and Bronchopulmonary Dysplasia in ambulatory follow-up of Low-Birth-Weight infants (LBWI) with oxygen-dependency in the outpatient Kangaroo Mother Care Program (KMCP). Theophylline's main metabolic product is caffeine; therefore, it was an alternative due to the frequent lack of ambulatory oral caffeine in low and middle-income countries.