Effect of age on cyclosporine pharmacokinetics in marrow transplant recipients

We have observed recently that infants and young children given cyclosporine (Cs) as graft-v-host disease prophylaxis usually have lower serum concentrations than adults given identical per kg doses. Studies in liver transplant recipients also indicate that Cs clearance is more rapid in children than in adults. However, data from this patient population are difficult to interpret because the liver is probably the major site of Cs metabolism. Moreover, most marrow transplant recipients receive high-dose chemotherapy either alone or combined with total body irradiation before marrow grafting, which may alter Cs metabolism during the early posttransplant period. Therefore, we analyzed the effect of age on Cs pharmacokinetics in marrow transplant recipients.