R. McGory

The pharmacokinetics of vancomycin were characterized in 56 patients with different degrees of renal function after an intravenous dose of 18.4 +/- 4.7 mg kg-1 (mean +/- standard deviation). Seven subjects had a creatinine clearance (CLCR) of greater than 60 ml min-1 (group I), 13 had a CLCR of 10 to 60 ml min-1 (group II), and 36 had a CLCR of less than 10 ml min-1 (group III). Serial serum samples (range, 3 to 8) were collected during the 168 h after drug administration. The serum concentration-time profile in all patients demonstrated monoexponential decay. The mean half-lives were 9.1, 32.3, and 146.7 h in groups I, II, and III, respectively. A significant decline in serum clearance (CLS) was also noted (62.7 to 28.3 to 4.87 ml min-1 in groups I, II, and III, respectively). The steady-state volume of distribution varied from 0.72 to 0.90 liter kg-1. There was no significant relationship between the steady-state volume of distribution and CLCR. The observed relationship between CLS and CLCR (CLS = 3.66 + 0.689 CLCR; r = 0.8807) can be utilized to devise dosage schedules for patients with any degree of renal impairment. This relationship was utilized to develop a nomogram for initial and maintenance dosing of vancomycin.

Passive immunization with hepatitis B surface antibody (anti-HBs) is important to prevent hepatitis B virus (HBV) recurrence after orthotopic liver transplantation for chronic HBV cirrhosis. Hepatitis B immune globulin (HBIG) dosing regimens have been poorly defined, utilize numerous routes of administration, and result in a high rate of HBV relapse and mortality. Twenty-five of 27 (93%) patients transplanted (four retransplants) for chronic HBV cirrhosis show no evidence of recurrent HBV (range, 2-55 months). Anti-HBs titers necessary to minimize the risk of hepatitis B surface antigen detectability were >500 IU/L for days 0 to 7, >250 IU/L for days 8 to 90, and >100 IU/L thereafter. Pretransplant HBV E antigen (HBeAG)-positive patients required more HBIG to achieve these goals than HBeAG-negative individuals. The elimination of anti-HBs changed continually for the initial 3 posttransplant months. The anti-HBs half-life increased from 0.7 days to 14.1 days. Anti-HBs elimination was significantly different in HBeAG+ and HBeAG- patients for the first week, but was subsequently indistinguishable after week 1. After 3 months, the half-life was statistically less for HBeAG+ patients, but the difference did not influence the clinical treatment regimens. Quantitative hepatitis B DNA levels did not predict the amount of HBIG required. HBV recurrence after orthotopic liver transplantation can be reduced by aggressive passive immunization. Pharmacokinetic analysis of anti-Hbs elimination can improve immunoglobulin therapy and prevent recurrence of clinical hepatitis.

OBJECTIVE: The goals were to summarize the results of liver transplantation for chronic hepatitis B disease (HBV) at the University of Virginia, correlate pretransplant viral markers with posttransplant hepatitis B immunoglobulin (HBIg) requirements, and identify the relation between viral protein in the liver and clinical reinfection. SUMMARY BACKGROUND DATA: Liver transplantation is an accepted treatment for end-stage liver disease from chronic HBV infection, although lifelong antiviral treatment (with HBIg or antiviral agents) is still necessary. Patients with evidence of active viral replication (detectable serum HBV-DNA or e antigen) at the time of transplant have a higher rate of allograft infection. Whether clinically stable patients receiving HBIg immunoprophylaxis have detectable viral products in their grafts remains unknown. METHODS: Forty-four transplants performed for HBV disease at the University of Virginia since March 1990 were reviewed. Most patients underwent aggressive passive immunoprophylaxis with HBIg to maintain serum HBV surface antibody (HBsAb) levels > or =500 IU/l for the first 6 months after the transplant, and > or =150 IU/l thereafter. Patients had viral markers quantified, underwent pharmacokinetic analysis of HBsAb levels to adjust dosing, and were biopsied routinely every 3 to 6 months and when indicated. RESULTS: Forty-four transplants were performed in 39 patients. Actual 1-year and 3-year graft survival was 95% and 81%, respectively, and 1-year and 3-year patient survival was 98% and 96%, respectively. After the adoption of indefinite HBIg prophylaxis, nine grafts became infected (all in recipients positive for HBV e antigen). Three occurred within 8 weeks of transplantation and were associated with a short HBsAb half-life and a wild-type virus. Six occurred >8 months after the transplant, and most of these were associated with viral mutation. Quantification of pretransplant markers was an overall poor predictor of HBIg requirements after the transplant. Immunohistochemistry demonstrated transient low-level expression of core protein in the liver in 23% of patients without serum or clinical evidence of recurrent hepatitis. CONCLUSIONS: An excellent outcome is possible after liver transplantation for chronic HBV disease using HBIg dosed by pharmacokinetic parameters. Currently, quantification of pretransplant serum markers of the HBV antigen load does not predict the intensity of posttransplant treatment required for good clinical outcomes. Because HBV is not eradicated from the patient, some form of indefinite antiviral therapy continues to be warranted.

BACKGROUND & AIMS: Prostaglandin E1 (PGE1) has been used after orthotopic liver transplantation (OLT) based on limited clinical data suggesting PGE1 infusion improves immediate hepatic allograft function. The aim of this study was to conduct a randomized double-blinded multicenter trial to evaluate the effect of PGE1 on early hepatic and renal function in patients undergoing OLT. METHODS: One hundred eighteen patients were randomized to receive either PGE1 or crystalloid placebo intravenously after allograft revascularization. Primary end points were incidence of primary allograft nonfunction (PNF) or severe renal dysfunction. RESULTS: The incidence of PNF was 6.7% (4 of 60) and 6.9% (4 of 58) in the control and PGE1 groups, respectively. PGE1 infusion was, however, associated with improved early renal function (mean peak creatinine level of 1.4 +/- 1.0 and 2.0 +/- 1.0 in patients treated with PGE1 and placebo, respectively; P < 0.001). Severe renal dysfunction occurred more frequently in the placebo group (26.7%) than in the PGE1 group (13.8%; P = 0.65). Additionally, dialysis treatments were more frequent in the placebo group (0.7 +/- 2.0 per patient) than in the PGE1 group (0.2 +/- 1.0 per patient; P = 0.10). Initial intensive care unit stay was shorter in patients treated with PGE1 (4.0 +/- 3.6 days) compared with controls (10.5 +/- 17.1 days) (P < 0.01). CONCLUSIONS: PGE1 administration after OLT resulted in improved renal function and decreased initial postoperative intensive care unit stay but did not affect the incidence of PNF.

BACKGROUND: An oral formulation of ganciclovir (GCV) was recently approved for the prevention of cytomegalovirus disease in solid organ transplant recipients. This study was designed to determine the bioavailability of GCV and to test a dosing algorithm in transplant and dialysis patients with different levels of renal function. METHODS: Pharmacokinetic studies were carried out in 23 patients who were either a recipient of an organ transplant or on hemodialysis. Drug dosing was established by the following algorithm based on calculated creatinine clearance (CrCl): CrCl = [(140-age) x body weight]/(72 x Cr) x 0.85 for women that is, CrCl >50 ml/min, 1000 mg every 8 hr; CrCl of 25-50 ml/min, 1000 mg every 24 hr; CrCl of 10-24 ml/ min, 500 mg every day; CrCl < 10 ml/min (or on dialysis), 500 mg every other day after dialysis. GCV was taken within 30 min after a meal. The patients received oral GCV for between 12 days and 14 weeks. Serum specimens (or plasma from patients on hemodialysis) obtained at steady state were analyzed for GCV concentrations by high-performance liquid chromatography. In nine of the transplant recipients, absolute bioavailability was determined by comparing GCV levels after single oral and intravenous doses of GCV. RESULTS: The following GCV concentrations (mean +/-SD) were determined: with CrCl of > or =70 ml/min, the minimum steady-state concentration (Cmin) and maximum concentration (Cmax) were 0.78+/-0.46 microg/ml and 1.42+/-0.37 microg/ml, respectively, with a 24-hr area under the concentration time curve (AUC0-24) of 24.7+/-7.8 microg x hr/ml; with CrCl of 50-69 ml/min, the Cmin and Cmax were 1.93+/-0.48 and 2.57+/-0.39 microg/ml, respectively, with an AUC0-24 of 52.1+/-10.1 microg x hr/ml; with CrCl of 25-50 ml/min, the Cmin and Cmax were 0.41+/-0.27 and 1.17+/-0.32 microg/ml, respectively, with an AUC0-24 of 14.6+/-7.4 microg x hr/ml. For one patient with a CrCl of 23.8 ml/min, the Cmin and Cmax were 0.32 and 0.7 microg/ml, respectively, with an AUC0-24 of 10.7 microg x hr/ml. With CrCl of <10 ml/min, the mean Cmin and Cmax were 0.75+/-0.42 and 1.59+/-0.55 microg/ml, respectively, with a mean AUC0-24 of 64.6+/-18.8 microg x hr/ml. Absolute bioavailability, for the nine patients so analyzed, was 7.2+/-2.4%. For those patients with end-stage renal failure, GCV concentrations fell during dialysis from a mean of 1.47+/-0.48 microg/ml before dialysis to 0.69+/-0.38 microg/ml after dialysis. CONCLUSIONS: The bioavailability of oral GCV in transplant patients was similar to that observed in human immunodeficiency virus-infected patients. However, levels between 0.5 and 1 microg/ml (within the IC50 of most cytomegalovirus isolates) could be achieved with tolerable oral doses. The proposed dosing algorithm resulted in adequate levels for patients with CrCl greater than 50 ml/min and for patients on dialysis. For patients with CrCl between 10 and 50 ml/min, the levels achieved were low and these patients would likely benefit from increased doses.