Blood ribavirin concentration in high-dose ribavirin for adenovirus-induced haemorrhagic cystitis - a case report.

Blood ribavirin concentration was monitored after the administration of high-dose oral ribavirin in a case of adenovirus-induced haemorrhagic cystitis post-stem-cell transplantation. Combination use of intravenous gamma immunoglobulin (15 g/3 days) and high-dose ribavirin (RBV; 9000 mg/4 days) provided plasma ribavirin concentration of 24.3 microM and achieved virus eradication. High level of erythrocyte ribavirin (1085 microM; mostly as phosphorylated metabolites) with long half-life (15 days) caused severe anaemia, which required several blood transfusions for 2 weeks after the cessation of the ribavirin treatment. It was suggested that blood transfusion and intensive haemoglobin level monitoring is necessary for at least 4 weeks after the RBV, because of the high accumulation of phosphorylated ribavirin in erythrocytes even after stopping ribavirin administration.