Effects of different routes of cyclosporin A administration on blood levels in patients undergoing bone marrow transplantation

This follow-up study has been carried out on 15 bone marrow transplant recipients treated intravenously with cyclosporin A (CsA) as a bolus (1.25-2.5 mg/kg/12 h) or by continuous infusion (1-3 mg/kg/24 h) from -2 until the 21st day after transplantation. All patients were subsequently treated with CsA orally at a starting dose of 6.25 mg/kg/12 h; this starting dose was then adjusted on the basis of CsA blood levels until the 60th day after transplantation, followed by progressive reduction and withdrawal within 6-12 months. In whole blood, trough levels of polyclonal (P) and monoclonal (M) CsA were monitored by a FPIA method and the polyclonal/monoclonal ratio (P/M) was calculated, This ratio was lower during CsA administration as a bolus or by continuous infusion than during oral administration; the decrease was statistically significant. This difference was probably due to first-pass metabolism which occurs in the liver and gut after oral administration.