Pharmacokinetics and pharmacodynamics of pravastatin in pediatric and adolescent cardiac transplant recipients on a regimen of triple immunosuppression

Background: In adults, pravastatin reduces the development and progression of transplant vasculopathy, the main long-term risk after cardiac transplantation. The pharmacokinetics of pravastatin is not known in children taking calcineurin inhibitors. Our aim was to determine the single-dose pharmacokinetics and short-term safety of pravastatin in children undergoing regular triple-drug immunosuppressive therapy after cardiac transplantation. Methods: Nineteen pediatric cardiac transplant recipients (aged 4.4 to 18.9 years) receiving triple immunosuppression therapy consisting of methylprednisolone (19 patients), cyclosporine (INN, ciclosporin) (17 patients) or tacrolimus (2 patients), and azathioprine (18 patients) or mycophenolate mofetil (1 patient) ingested a single 10-mg dose of pravastatin, and plasma pravastatin concentrations were measured up to 24 hours. Subsequently, the patients took 10 mg pravastatin orally once daily for 8 weeks. The lipid-lowering effect and the safety of pravastatin therapy were studied. Results: The mean peak plasma concentration (C-max) of pravastatin was 122.2 +/- 88.2 ng/mL (range, 11.4-305.0 ng/mL), and the area under the plasma concentration-time curve of pravastatin from 0 to 10 hours [AUC(0-10)] was 264.1 +/- 192.4 ng (.) h/mL (range, 30.8-701.6 ng (.) h/mL). These C-max and AUC(0-10) values are nearly 10-fold higher than the corresponding values reported in hypercholesterolemic children in the absence of immunosuppressive therapy. The time of peak concentration (t(max)) of pravastatin was 1.1 +/- 0.4 hours (range, 0.5-2 hours), and the mean elimination half-life (t(1/2)) was 1.2 +/- 0.3 hours (range, 0.7-2.2 hours); these parameters were similar to those in the hypercholesterolemic children. By 8 weeks of treatment, the concentration of serum total cholesterol decreased by 13% (P = .005), low-density lipoprotein cholesterol by 27% (P < .0001), and triglycerides by 6% (not significant, P = .28); the concentration of high-density lipoprotein cholesterol increased by 7% (not significant, P = .30). No clinically significant increases in serum ALT, creatine kinase, or creatinine levels were observed. Conclusions: The plasma concentrations of pravastatin in pediatric cardiac recipients receiving triple immunosuppressive medication are nearly 10-fold higher than in hypercholesterolemic children after the same pravastatin dose. However, the short-term therapy of pravastatin was well tolerated and effective in lowering serum cholesterol levels in cardiac recipients.