Use and prescribing patterns for erythropoiesis-stimulating agents in inpatient and outpatient hospital settings.

PURPOSE: Erythropoiesis-stimulating agent (ESA) use in the outpatient and inpatient settings through pharmacist-conducted, hospital-based chart audits is examined and discussed. METHODS: Data from four hospital chart audits conducted in 250 hospitals between October 2005 and July 2006 were pooled for analyses. Eligible hospitals were categorized by ESA sales volume, with approximately equal numbers randomly selected from each decile. The last five inpatients and outpatients within each specified month receiving either darbepoetin alfa or epoetin alfa were evaluated. Study variables by setting included ESA use, prescriber specialty, and dosage regimen. RESULTS: The most common hospital locations of ESA administration were a cancer center in the outpatient setting (49%) and general medicine (57%) in the inpatient setting. ESA prescribers were most commonly hematologists and oncologists in the outpatient setting, and nephrologists were the most common prescribers in the inpatient setting. In the outpatient analysis, 2155 patients were prescribed darbepoetin alfa and 3106 were prescribed epoetin alfa. The predominant administration frequencies were every two weeks and once weekly for darbepoetin alfa, and once weekly for epoetin alfa. In the inpatient analysis, 1633 patients were prescribed darbepoetin alfa and 3231 were prescribed epoetin alfa. The predominant administration frequencies were once weekly for darbepoetin alfa and once weekly and three times weekly for epoetin alfa. Common uses for both ESAs were chemotherapy-induced anemia (outpatient setting) and anemia of end-stage renal disease with chronic dialysis (inpatient setting). There was considerable variability in ESA dosages and administration frequencies in both settings within all patient groups when analyzed by specified use. CONCLUSION: ESA use differed between outpatient and inpatient settings in indication, frequency of administration, and specialty of the prescriber.

Evaluation of an in vitro dialysis system to predict drug removal.

BACKGROUND: Variation in the extent of drug removal under different dialysis conditions presents a challenge for prediction of drug elimination and dosage regimen adjustment during haemodialysis (HD). Dependence on clinical pharmacokinetic studies in HD patients for dosing guidelines is problematic given the increasing number of dialysers with variable rates of drug removal. Thus, the purpose of this study was to characterize drug removal using an in vitro system and to evaluate its reliability to predict in vivo elimination by HD using vancomycin (VANC) as a model drug. METHODS: In vitro dialysis was performed for 2 h (volume 4.0 l normal saline, initial VANC concentration 30 mg/l, flow rate 300 ml/min, dialysate flow 800 ml/min) using four different dialysers: polymethylmethacrylate (BK-2.1 U), polysulfone (F-80), AN69 (Filtral-20) and hemophan (COBE 700HE). The in vitro dialysis clearance for VANC (CL(D)) for the polysulfone dialyser was compared with values determined in eight HD patients. In vitro VANC CL(D) for all dialysers was compared with the clearance and KoA for B12 reported for each dialyser. RESULTS: In vitro VANC CL(D) values were 93+/-11 ml/min for the polymethylmethacrylate BK-2.1, 136+/-7 ml/min for the AN69, 65+/-9 ml/min for the hemophan COBE 700HE and 143+/-10 ml/min for the polysulfone F80. The CL(D) for the polysulfone F80 was not statistically different from the in vivo CL(D) of 135+/-18 ml/min (P = 0.48). In vitro VANC CL(D) correlated with the B12 CL(D) (r(2) = 0.77) and the B12 KoA (r(2) = 0.63) reported for each dialyser. CONCLUSION: VANC CL(D) in HD patients for the polysulfone dialyser was correctly predicted using the in vitro dialysis system. Use of this system may be superior to estimations of drug CL(D) based on dialyser information provided by the manufacturer for compounds of similar molecular weight.