Prodrug administration
Prodrugs were administered on an outpatient basis. 5-Fluorocytosine (Ancobon; Roche Laboratories, Basel, Switzerland) was administered orally beginning on day 3 and continued for 1 week (7 days). A total of 150 mg/kg/day was given in four equally divided doses. Valganciclovir (Valcyte; Roche Laboratories) was administered orally beginning on day 3 and continued for 1 week (7 days). A total of 1,800 mg/day was given in two equally divided doses every 12 h. The research nurse assigned to the trial counted the pills periodically to monitor patient compliance.