COMPARISON OF PHENYTOIN SERUM CONCENTRATIONS IN PREMATURE NEONATES FOLLOWING INTRAVENOUS AND ORAL-ADMINISTRATION

OBJECTIVE: TO compare the serum concentrations attained following intr avenous and oral administration of phenytoin in premature neonates. DE SIGN: A prospective, uncontrolled study was conducted over 6 years, Ph enhydan concentrate for infusion (Desitin, Hamburg, Germany) was used for intravenous infusion, and Epanutin suspension (Parke-Davis, Freibu rg, Germany) was used for oral therapy. Blood samples were analyzed by using a fluorescence polarization immunoassay analyzer TDx model by A bbott Laboratories. SETTING: A university-affiliated district hospital . PARTICIPANTS: Twenty premature neonates who were administered intrav enous and/or oral phenytoin between February 1991 and February 1997. M AIN OUTCOME MEASURES: Serum phenytoin concentrations on intravenous an d oral phenytoin. RESULTS: Nine patients received intravenous (group A ) and 15 patients received oral (group B) therapy. Mean +/- SD postnat al age (41 +/- 8.7 vs. 48 +/- 17 d; p = 0.03) and actual body weight ( 1.56 +/- 0.38 vs. 1.88 +/- 0.75 kg; p = 0.02) were slightly higher in group B. There were no significant differences between the groups in m ean +/- SD gestational age (26.1 +/- 1.37 vs. 26.9 +/- 3.30 wk), 5-min ute Apgar score (8.7 +/- 1.11 vs. 7.7 +/- 2.26), daily dosage (8.1 +/- 3.86 vs. 8.1 +/- 4.21 mg/kg/d), and phenytoin serum concentration (8. 7 +/- 7.36 vs. 9.6 +/- 5.83 mu g/mL). CONCLUSIONS: Contrary to data in the current literature, reliable serum concentrations in premature ne onates were achieved by oral administration of phenytoin suspension. O ral therapy offers a number of advantages and considerably reduces the cost of therapy. Due to substantial variations in phenytoin pharmacok inetics in neonates, close monitoring of serum concentrations is requi red. Further investigation is required to confirm these results, espec ially in neonates younger than 20 days' postnatal age and those receiv ing products other than Epanutin.