Oral valganciclovir in children: single dose pharmacokinetics in a six-year-old girl.

We report a pharmacokinetic study in a 6-year-old girl with congenital human immunodeficiency virus type 1 and cytomegalovirus coinfection maintained on iv ganciclovir for 6 years. Increasing infection and thrombosis caused by her iv device necessitated alternative therapy. Single dose pharmacokinetics of ganciclovir 4.4 mg/kg iv and valganciclovir 13.2 and 26.3 mg/kg po were studied with high performance liquid chromatography/tandem mass spectrometry. The two oral dosages yielded areas under the concentration curve of 14.3 and 28.7 microg x h/ml, equivalent to 43% bioavailability of ganciclovir from valganciclovir, which exceeded the area under the concentration curve of 11.1 microg x h/ml yielded by ganciclovir 4.4 mg/kg iv. Oral valganciclovir achieved therapeutic and dosage-proportional plasma concentrations in the child we studied.