Monitoring plasma levels of ganciclovir in AIDS patients receiving oral ganciclovir as maintenance therapy for CMV retinitis

Objective To investigate whether low ganciclovir serum levels in patients on maintenance oral ganciclovir therapy are associated with recurrence of CMV retinitis. Methods A prospective study of the plasma concentration of ganciclovir after initiation of maintenance oral ganciclovir therapy in 14 AIDS patients who had recovered from acute cytomegalovirus (CMV) retinitis. Results Five of the 14 patients exhibited a mean time to recurrence of 37 days. The mean trough plasma concentration of ganciclovir in these patients after 1 month of oral ganciclovir therapy, was 0.40 +/- 0.30 mg/L. Nine patients had a mean time of progression of 263 days. The mean trough plasma concentration of ganciclovir in the latter patients was 0.80 +/- 0.60 mg/L. Conclusions Patients exhibiting trough plasma levels of ganciclovir below 0.6 mg/L may be at higher risk of progression than patients who exhibited levels above 0.6 mg/L.