LOW PLASMA-CONCENTRATIONS ACHIEVED WITH CONVENTIONAL SCHEDULES ADMINISTRATION OF GANCICLOVIR IN PATIENTS WITH AIDS

Plasma concentration of ganciclovir was studied prospectively in 15 AI DS patients treated for acute cytomegalovirus (CMV) retinitis. Gancicl ovir was administered at a mean dose of 10.3 +/- 0.6 mg/kg/day. The me an trough plasma concentration was 0.6 +/- 0.3 mg/L (n = 24), and the mean peak concentration was 7.2 +/- 2.4 mg/L (n = 6). In 12 patients, trough concentrations were below the range that has been associated wi th effective treatment. Low trough concentrations were associated with treatment failure in 6 patients. Following an increase in the daily d ose, improvement was observed in 4 of the 6 patients. These results su ggest that low plasma ganciclovir levels are associated with the failu re of therapy, Monitoring the plasma concentration of ganciclovir may thus be useful before considering the virus to be resistant to the dru g or before switching from ganciclovir to foscarnet.