Pain comparison after subcutaneous administration of single-dose formulation versus multidose formulation of epogen in hemodialysis patients.

Subcutaneous (s.c.) injection is an approved route of administration for recombinant human erythropoietin (epoetin alfa). However, pain at the injection site with the single-dose formulation has limited its use. With the recent development of a multidose formulation containing benzyl alcohol as a preservative, anecdotal reports have emerged that suggest this product causes less stinging. Using a randomized, triple-blind, placebo-controlled crossover design, this study compared pain perception, intensity, and duration after s.c. injection with a multidose formulation versus single-dose formulation using visual analogue (VAS) and verbal descriptive pain scales (VDS). Twenty-eight hemodialysis patients received s.c. injections of placebo (normal saline) in one arm and either the multidose or single-dose formulation in the opposite arm. One week later, the subjects again received placebo in one arm and the other epoetin alfa formulation in the opposite arm. The VAS and VDS measurements were obtained at time 0 and then every 5 minutes for a period of 30 minutes. Results showed a statistically significant difference in pain perception between formulations at times 0, 10, and 15 minutes for both the VAS and VDS. In conclusion, there was a significant difference in pain perception between formulations with the multidose formulation causing less pain than the single-dose formulation. However, it should be noted that several patients reported no pain with the single-dose formulation. This indicates that individual patient response could be considered when deciding which formulation to use, although it may be difficult to implement an error-free distribution and administration system using the two different formulations.

Predictive performance of renal function estimate equations in renal allografts.

AIMS: Various mathematical models have been developed to estimate glomerular filtration rate (GFR) incorporating variables such as age, gender, height, weight, serum creatinine, and body surface area (BSA). Because adjustments in drug dosing are often based on estimated values of renal function, it is important to define which, if any, of the available models, is appropriate for a specific patient population. A study was undertaken to determine the bias and precision of four mathematical models to estimate GFR in renal allograft recipients. METHODS: A retrospective review of 142 stable renal allograft patients, using iohexol clearance as a determinant of GFR, was performed. Renal allograft recipients followed in an outpatient clinic setting underwent iohexol clearance studies as part of clinical monitoring in the post-transplant period. Measured GFR values were compared with four mathematical models used to estimate GFR: the Cockcroft-Gault equation, the Jelliffe equation, the Walser equation, and the Mawer equation. Bias and precision were determined for each model as the mean squared error and the mean squared error, respectively. RESULTS: Patients had a mean age of 44 +/- 13 years, 92 were male, and 50 were female. The serum creatinine concentration was 176.8 +/- 88.4 mumol l-1 (mean +/- s.d.). The mean time post-transplant was 5.1 +/- 5.0 years and 38% of patients had insulin-requiring diabetes mellitus. The bias and precision results for the Jelliffe, Walser, Cockcroft-Gault, and Mawer models were: -3 and 414; -5 and 381; 16 and 688; and 23 and 1084, respectively. CONCLUSIONS: The Jelliffe and Walser equations gave the least biased and most precise estimations of GFR when compared with iohexol-derived measures in patients with renal allografts.

Accuracy of technicians versus pharmacists in checking syringes prepared for a dialysis program.

The accuracy of pharmacy technicians versus pharmacists in checking drug doses prepared in syringes for a dialysis program was studied. Three pharmacy technicians from the pharmacy of a regional kidney disease program in Minnesota participated in the study after completing a training program and after common preparation errors had been identified by pharmacists. From November 1995 to April 1996, the technicians used labels printed from a database of pharmacist-verified orders to prepare and label i.v. syringes. Four medications were used-epoetin alfa, calcitriol, heparin prepared from beef lung, and heparin prepared from porcine intestinal mucosa. Each syringe was checked by one of nine pharmacists for accuracy of dose and medication, and all errors were recorded. The technicians checked syringes prepared by other technicians and also recorded errors. Accuracy rates (percentages of syringes correctly evaluated) for pharmacists and technicians were compared. A total of 10,608 syringes were checked. Accuracy rates for pharmacists and pharmacy technicians were 99.86% and 99.83%, respectively. Accuracy rates in checking syringes did not differ significantly between pharmacists and technicians in this study setting.

Randomized cross-over study of adverse reactions and cost implications of intravenous push compared with infusion of iron dextran in hemodialysis patients.

In many dialysis centers, iron dextran is administered by intravenous infusion rather than intravenous push (the method of administration recommended in the package insert) as a possible, but unproven, means to reduce side effects. This study was performed to determine whether there is a difference in adverse reactions between these two methods. Ten iron-deficient hemodialysis patients participated in a randomized, cross-over study of iron dextran 100 mg administered by intravenous push over 2 minutes (undiluted) or as a 30-minute intravenous infusion during the first hour of hemodialysis. Patients received a total of four doses (two by each method during four separate dialysis sessions). Blood pressure and heart rate were monitored pre-dose and at frequent intervals throughout the hemodialysis session following the dose. Patients completed adverse event surveys before and 60 minutes after the dose and prior to the next hemodialysis session. Blood pressure, heart rate, and survey data were analyzed using a Wilcoxon analysis (P

Cholesterol-lowering effects of calcium carbonate in patients with mild to moderate hypercholesterolemia.

BACKGROUND: In recent years, several authors have noted that oral calcium treatment was associated with a reduction in serum cholesterol level. METHODS: Calcium carbonate was examined for its ability to lower serum cholesterol levels in hypercholesterolemic patients. Fifty-six patients with mild to moderate hypercholesterolemia were examined in this randomized, double-blind, placebo-controlled crossover study. Patients were treated with a low-fat, low-cholesterol diet targeted at the American Heart Association Step-1 diet for 8 weeks before and while receiving placebo or calcium carbonate (9.98 mmol [400 mg] of elemental calcium) three times daily with meals for 6 weeks. Patients were then crossed over to the alternate treatment for an additional 6-week period. RESULTS: Compared with placebo, calcium carbonate achieved a 4.4% reduction in the low-density lipoprotein cholesterol level, and a 4.1% increase in the high-density lipoprotein cholesterol level. The ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol significantly decreased by 6.5% with calcium carbonate treatment. Calcium carbonate treatment did not significantly affect blood pressure or serum levels of triglycerides, lipoprotein Apo B, or calcium. Relative urinary saturation ratios of calcium oxalate levels were unchanged during calcium carbonate therapy. Compliance with diet and treatment was excellent and no significant adverse effects were noted. CONCLUSIONS: Thus, calcium carbonate was a modestly effective and well-tolerated adjunct to diet in the management of mild to moderate hypercholesterolemia in this clinical study.

Epoetin enhances erythropoiesis in normal men undergoing repeated phlebotomies.

Epoetin may enhance autologous blood donation, but efficacy and dose response have not been established. This multicenter, double-blind trial compared intravenous placebo (n = 23) with epoetin beta, 250 U/kg (n = 23), 500 U/kg (n = 19), and 1000 U/kg (n = 22), administered three times weekly for 26 days. Normal men (age, 28 +/- 7 years; mean +/- SD) received phlebotomies up to three times weekly as long as the hemoglobin remained greater than or equal to 12 gm/dl. Subjects treated with epoetin donated 32% more units of blood (p less than 0.05) compared with placebo. A dose response was not observed. Platelet counts increased with epoetin compared with placebo, but platelet function and bleeding time did not change. Prothrombin times increased and partial thromboplastin times decreased with both epoetin and placebo. The supernatant of packed red blood cells collected after multiple phlebotomies and stored 42 days had slightly lower glucose concentrations and pH after therapy with epoetin. Blood pressure did not change with epoetin or placebo. These findings support the efficacy and safety of epoetin for enhancing the erythropoietic response of normal subjects during intensive phlebotomy.

Comparative pharmacokinetics and pharmacodynamics of epoetin alfa and epoetin beta.

Different recombinant human erythropoietin products have been developed. Although they appear to have similar pharmacokinetics and function, these have not been directly compared. This randomized, double-blind, four-period crossover study compared the pharmacokinetics and pharmacodynamics of intravenous and subcutaneous epoetin alfa and epoetin beta in 18 normal male volunteers. As a control, three subjects received placebo treatment. After intravenous administration, the steady-state volume of distribution and beta-phase volume of distribution of epoetin beta were 7.7% and 16.9% larger than for epoetin alfa (p less than 0.05). The terminal elimination half-life after intravenous administration of epoetin beta was 20% longer than the terminal elimination half-life of epoetin alfa. After subcutaneous administration there was a delayed drug absorption with epoetin beta compared with epoetin alfa (p less than 0.05). There was a small but significantly greater absolute reticulocyte response after subcutaneous epoetin beta compared with subcutaneous epoetin alfa. The findings support differences in the pharmacokinetics and function of epoetin alfa and beta that are possibly caused by differences in their glycosylation.

Blood pressure in hemodialysis patients during amelioration of anemia with erythropoietin.

This study analyzed blood pressure in hemodialysis patients treated with epoetin beta in multicenter trials. Antihypertensive drugs were prescribed as usual. Placebo-controlled trials compared epoetin (100 to 150 U/kg; N = 151) with placebo (N = 78) for 82 days. Hemoglobin (108 +/- 18 versus 75 +/- 14 g/L) (mean +/- SD) and diastolic blood pressure (84 +/- 14 versus 78 +/- 15 mm Hg) were greater (P less than 0.05) after epoetin. Clinically important increases in blood pressure (increases in diastolic blood pressure greater than or equal to 10 mm Hg and/or drug therapy) were more frequent with epoetin (58 versus 37%; P = 0.005). A dose-response trial compared epoetin, 25 U/kg (N = 42), 100 U/kg (N = 40), and 200 U/kg (N = 39) for 138 days. Increases in hemoglobin were dose dependent, but clinically important increases in blood pressure were not. In analyses of all patients treated with epoetin (N = 272), no baseline or final level of hemoglobin, or rate of hemoglobin rise, was a threshold for a rise in blood pressure. Patients requiring antihypertensive drugs or having uncontrolled hypertension (diastolic blood pressure greater than 90 mm Hg) at baseline had decreases in blood pressure (P less than 0.05) with antihypertensive therapy. Thus, compared with placebo, 21% of patients had clinically important increases in blood pressure during amelioration of anemia. The baseline or final levels of hemoglobin, the extent or rate of hemoglobin rise, or uncontrolled hypertension or antihypertensive drug use at baseline were not confirmed as risks. Antihypertensive drug therapy was important for blood pressure control.

A controlled trial of intravenous immunoglobulin G in chronic fatigue syndrome.

PURPOSE: Currently, there is no established therapy for chronic fatigue syndrome (CFS), a recently defined illness that has been associated with a variety of immunologic abnormalities. Based on the hypothesis that a chronic viral infection or an immunoregulatory defect is involved in the pathogenesis of CFS, the therapeutic benefit of intravenous immunoglobulin G (IV IgG) was evaluated in a group of patients with CFS. Additionally, serum immunoglobulin concentrations and peripheral blood lymphocyte subset numbers were measured at the outset of the study, and the effect of IV IgG therapy on IgG subclass levels was determined. PATIENTS AND METHODS: Thirty patients with CFS were enrolled in a double-blind, placebo-controlled trial of IV IgG. The treatment regimen consisted of IV IgG (1 g/kg) or intravenous placebo (1% albumin solution) administered every 30 days for 6 months. Participants completed a self-assessment form prior to each of the six treatments, which was used to measure severity of symptoms, functional status, and health perceptions. Patients were also asked to report adverse experiences defined as worsening of symptoms occurring within 48 hours of each treatment. RESULTS: Twenty-eight patients completed the trial. At baseline, all 28 patients complained of moderate to severe fatigue, and measures of social functioning and health perceptions showed marked impairment. Low levels of IgG1 were found in 12 (42.9%), and 18 (64.3%) had low levels of IgG3. At the end of the study, no significant therapeutic benefit could be detected in terms of symptom amelioration or improvement in functional status, despite restoration of IgG1 levels to a normal range. Major adverse experiences were observed in 20% of both the IV IgG and placebo groups. CONCLUSION: The results of this study indicate that IV IgG is unlikely to be of clinical benefit in CFS. In addition to the ongoing need for placebo-controlled trials of candidate therapies for CFS, an expanded research effort is needed to define the etiology and pathogenesis of this disorder.

Suppression of ventricular fibrillation and positive inotropic action of bethanidine sulfate, a chemical analog of bretylium tosylate that is well absorbed orally.

Bethanidine sulfate is a closely related chemical analog of bretylium that has virtually identical pharmacologic and antifibrillatory actions on the ventricle. Unlike bretylium, which is very poorly absorbed from the gut, bethanidine is rapidly and effectively absorbed after oral administration. Bethanidine increased ventricular fibrillation threshold in the normal dog heart from an average control value of 28.5 mA to an average peak value of 66.5 mA, an increase of 150 percent. In the infarcted heart, bethanidine increased ventricular fibrillation threshold from an average postinfarction level of 14.4 mA to an average peak value of 55.3 mA, an increase of 327 percent. Like bretylium, the antifibrillatory action of bethanidine was manifested by the appearance of nonsustained ventricular fibrillation when superthreshold shocks induced episodes of ventricular fibrillation lasting from 2 to 120 seconds and converting spontaneously to sinus rhythm. In contrast, the untreated dog heart must always be defibrillated electrically. The onset of antifibrillatory action began as early as 2 minutes after intravenous administration and 15 to 30 minutes after oral administration; peak action occurred in approximately 60 minutes. Bethanidine had prolonged positive inotropic action in the isolated heart as reflected by an increase in cardiac output and blood pressure lasting up to 60 minutes. Bethanidine lowered coronary vascular resistance and increased coronary blood flow. The oral efficacy and rapid onset of action gives bethanidine a potential role in the prevention of out-of-hospital ventricular fibrillation.