Population pharmacokinetics of ganciclovir after intravenous ganciclovir and oral valganciclovir administration in solid organ transplant patients infected with cytomegalovirus

A population pharmacokinetics analysis was performed after intravenous ganciclovir and oral valganciclovir in solid organ transplant patients with cytomegalovirus. Patients received ganciclovir at 5 mg/kg of body weight (5 days) and then 900 mg of valganciclovir (16 days), both twice daily with dose adjustment for renal function. A total of 382 serum concentrations from days 5 and 15 were analyzed with NONMEM VI. Renal function given by creatinine clearance (CL(CR)) was the most influential covariate in CL. The final pharmacokinetic parameters were as follows: ganciclovir clearance (CL) was 7.49.(CL(CR)/57) liter/h (57 was the mean population value of CL(CR)); the central and peripheral distribution volumes were 31.9 liters and 32.0 liters, respectively; intercompartmental clearance was 10.2 liter/h; the first-order absorption rate constant was 0.895 h(-1); bioavailability was 0.825; and lag time was 0.382 h. The CL(CR) was the best predictor of CL, making dose adjustment by this covariate important to achieve the most efficacious ganciclovir exposure.

Sirolimus in heart transplantation: a single center initial experience

Sirolimus (SRL) is a potent non-nephrotoxic immunosuppressant. In our unit, SRL was administered to 17 heart transplant (HT) recipients at 1770+/-1234 days' posttransplant surgery, for the following reasons: (1) calcineurin inhibitor (CI) withdrawal due to renal insufficiency (RI; n=6); (2) neurotoxicity (n=1) and pancytopenia (n=1); (3) vascular graft disease (VGD) treatment (n=5); (4) immunosuppression optimization due to lung cancer (n=2); (5) CI use was delayed due to postsurgery RI (n=2). The mean follow-up was 190+/-165 days. Mean SRL doses (mg)/concentrations (ng/mL) at 7 (n=17), 30 (n=14), and 180 (n=8) days were: 1.2+/-0.6/5.9+/-6; 1.6+/-0.8/4.8+/-3.1; and 1.7+/-1.0/5.2+/-3.7. Among group 1, CI patients were discontinued without favorable functional impact. Neurotoxicity and pancytopenia improved, but there were no major clinical events in the VGD group. One "bridge" to CI was successfully performed (postsurgery RI). Total leukocyte count fell while hemoglobin, platelet, and cholesterol profiles were not affected. Ten of 15 patients (67%) were discontinued from CI without rejection and with a dose reduction of mycophenolate mofetil. There were 8 episodes (47%) of SRL-related toxicity, leading to 4 discontinuations (23%); 8 patients (47%) have died during follow-up. This retrospective analysis of outcomes in the context of severe complicated patients suggests that more premature introduction SRL is preferable, particularly in a large patient cohort.