In the preliminary group of premature infants, those receiving q 6h dosing had an average trough concentration of 7.3 uM (18%). However, the premature infants in the preliminary pharmacokinetic study did not have long term follow-up to assess toxicity. Due to the potential for altered ZDV pharmacokinetics and increased toxicity in this population, an evaluation of ZDV pharmacokinetics in premature infants is proposed.
Premature infants less than or equal to 34 weeks gestational age at birth and begun on ZDV by their clinical caregivers will be entered into the protocol within the first 5 days of life. Upon entry, ZDV will be administered every 12 hours intravenously or orally. The study will require 9 serum samples for ZDV assay collected over 30 days, some additional clinical laboratory tests collected over 12 weeks, collection of 3 spot urine samples, and collection of routine clinical data.