POPULATION PHARMACOKINETICS OF CAFFEINE IN NEONATES AND YOUNG INFANTS

The population pharmacokinetics of caffeine were investigated in 60 ne onates and young infants using data collected during routine therapeut ic drug monitoring. Clearance was influenced by body weight and postna tal age, and increased in the presence of dexamethasone. No clinical f actors were identified that influenced volume of distribution. The pop ulation pharmacokinetic parameter estimates were then tested prospecti vely in a further 20 neonates. Although they produced unbiased results , the dexamethasone effect could not be identified. A final analysis u sing all 80 patients found clearance (L/day) = 0.14 x weight (kg) + 0. 0024 x postnatal age (days) (+/-20%) and volume of distribution = 0.82 L (+/-24%). Simulations based on these results indicated that the cur rent dosage guidelines of 20 mg/kg loading dose of caffeine citrate fo llowed by a 5 mg/kg/day maintenance dose should achieve concentrations within the traditional target range in >70% of neonates.