Pharmacokinetic profile and variability of cyclosporine versus neoral in patients with cystic fibrosis after lung transplantation.

Abstract

Various factors may influence bioavailability and blood concentrations of cyclosporine, a problem that may be compounded by diseases such as cystic fibrosis in which impaired absorption through the gastrointestinal tract is common. Neoral, a microemulsion formulation of cyclosporine, has improved bioavailability and more stable blood concentrations than earlier formulations. We conducted a prospective, open, crossover study to examine whether these findings held true in 12 clinically stable patients with cystic fibrosis who had undergone lung transplantation at least 6 months earlier. In the first arm, patients continued their usual dosage of cyclosporine twice/day. In the second arm they received Neoral for at least 1 week before having blood studies. For each arm whole blood trough concentrations were drawn for 7-10 successive days, together with a pharmacokinetic study with concentrations drawn at times zero, 1, 2, 3, 4, 6, 12, and 24 hours. Variance was assessed from morning concentrations. Area under the curve from zero to 12 hours (AUC12), maximum concentration (Cmax), and time to Cmax (Tmax) were calculated for each arm. Eleven subjects completed the protocol. The daily variance for Neoral was significantly less than for cyclosporine (p=0.04). The AUC12 for Neoral and cyclosporine were 4164+/-1467 and 5318+/-1670 microg x L/hour (p=0.09), respectively. Respective Cmax were 613+/-242 and 931 +/-458 microg/L (p=0.08) and relative Cmax and AUC12 were 1.91 and 1.47 (p<0.05). Thus Neoral had a superior pharmacokinetic profile and less day-to-day variability in patients with cystic fibrosis who had undergone lung transplantation.