Caffeine pharmacokinetics in preterm infants older than 2 weeks.

: We studied 17 preterm infants receiving caffeine, and measured their plasma levels of caffeine and the theophylline metabolite by high-pressure liquid chromatography. The half-life was calculated by computer analysis using the least-square method. The mean gestational age of our patients was 29.7 +/- 1.9 weeks (mean +/- SD) and they were studied at 20.7 +/- 6.6 days (mean +/- SD) postnatal age. The caffeine half-life was 52.03 +/- 23.87 h (means +/- SD) and the theophylline half-life was 77.04 +/- 65.01 h (mean +/- SD).