Developmental changes of caffeine elimination in infancy.

Five neonates (4 premature) and 16 infants (6 prematurely born), 15-588 days old, received caffeine as citrate salt for apnea. Plasma samples were collected 0, 2, 4, 6 h after a dose and before the next scheduled one. Patients 8 and 9 were serially studied. Caffeine plasma concentrations were determined using HPLC. The caffeine elimination half-life and clearance varied linearly with gestational age and exponentially with postnatal age, the plateau being reached during the second trimester of life. Dose regimen guidelines as a function of postnatal age were derived from individually calculated doses and dosing intervals in order to achieve, at steady state, a caffeine mean plasma concentration of 11 mg/l with a minimum of 7.5 mg/l and a maximum of 14.5 mg/l. We suggest dosing intervals for infants before 1 month, 1-2 months, 2-4 months and after 4 months to be equal to 24, 12, 8 and 6 h, respectively. The individual recommended dose varies from 2 to 10 mg/kg (as caffeine base) making caffeine monitoring mandatory in infants.