A Nurse Is Caring for an Infant After a Surgical

A nurse is caring for an infant after a surgical procedure. After ensuring that the ordered dose is appropriate for the infant's age and weight, the nurse administers a narcotic analgesic intravenously. When assessing the infant 15 minutes later, the nurse notes respirations of 22 breaths per minute and a heart rate of 110 beats/min. The infant is asleep in the parent's arms and does not awaken when vital signs are assessed. The nurse understands that these findings are the result of:

A) an allergic reaction to the medication.
B) immaturity of the blood-brain barrier in the infant.
C) toxic effects of the narcotic, requiring naloxone as an antidote.
D) unexpected side effects of medications in infants.