Safety aspects of parenteral iron in patients with end-stage renal disease

Short-term benefits and risks of intravenous iron: a systematic review and meta-analysis

BACKGROUND

Intravenous (IV) iron may correct anemia more efficiently than oral iron, but it has been associated with allergic and hemodynamic reactions, and it may increase the risks of infectious complications. The objective of this systematic review and meta-analysis was to clarify these controversial issues.

STUDY DESIGN AND METHODS

Studies evaluating the use of IV iron compared to enteral or no iron with outcomes within 2 months of treatment initiation were identified. Only randomized controlled trials were included. When a meta-analysis was possible, studies were combined with the Review Manager of the Cochrane Collaboration Group 2003. Statistics were calculated as standardized mean differences (SMDs), with a random-effect model.

RESULTS

Thirteen studies met inclusion criteria. Meta-analysis revealed a significant increase in the reticulocyte count (SMD, 0.70; 95% confidence interval [CI], 0.10-1.29; p = 0.02) and in ferritin levels (SMD, 1.18; 95% CI, 0.69-1.68; p = 0.00001), but it also showed that in such a short period of time, IV iron does not correct hemoglobin (Hb)-hematocrit (Hct) better than enteral or no iron. In a sensitivity analysis, however, the increase in Hb-Hct became significant in the nondextran group (SMD, 0.27; 95% CI, 0.04-0.51; p = 0.02). No increase in transferrin saturation was observed. Meta-analysis of the allergic and hemodynamic reactions was not possible as most studies did not clearly describe these outcomes.

CONCLUSION

Our results suggest that treatment with nondextran IV iron may benefit a wide variety of patients. Randomized controlled studies are definitively needed to further evaluate the usefulness and safety of IV iron.

Iron therapy for renal anemia: how much needed, how much harmful?

Iron deficiency is the most common cause of hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) in end-stage renal disease (ESRD) patients. Iron deficiency can easily be corrected by intravenous iron administration, which is more effective than oral iron supplementation, at least in adult patients with chronic kidney disease (CKD). Iron status can be monitored by different parameters such as ferritin, transferrin saturation, percentage of hypochromic red blood cells, and/or the reticulocyte hemoglobin content, but an increased erythropoietic response to iron supplementation is the most widely accepted reference standard of iron-deficient erythropoiesis. Parenteral iron therapy is not without acute and chronic adverse events. While provocative animal and in vitro studies suggest induction of inflammation, oxidative stress, and kidney damage by available parenteral iron preparations, several recent clinical studies showed the opposite effects as long as intravenous iron was adequately dosed. Thus, within the recommended international guidelines, parenteral iron administration is safe. Intravenous iron therapy should be withheld during acute infection but not during inflammation. The integration of ESA and intravenous iron therapy into anemia management allowed attainment of target hemoglobin values in the majority of pediatric and adult CKD and ESRD patients.

Haemodialysis-associated anaphylactic and anaphylactoid reactions

Anaphylactic and anaphylactoid reactions related to haemodialysis have been increasingly described for almost 3 decades. The majority of these cases used to occur with ethylene oxide sterilized, and complement-activating cellulose membranes. However, a considerable number of publications have focused on polyacrylonitrile AN69 high flux membranes, angiotensin converting enzyme inhibitors and iron as other important causes of potentially severe haemodialysis-related anaphylactoid reactions. Clinical manifestations vary considerably and generally do not allow differentiation between IgE-mediated anaphylaxis and anaphylactoid reactions (e.g. from nonspecific mediator release). Successful management of these patients requires multidisciplinary approach and involves prompt recognition and treatment by the attending physician, and identification of the offending agent(s) with subsequent avoidance of the incriminated compound(s). This review focuses on some major causes of anaphylactoid and anaphylactic reactions during haemodialysis. Special consideration is given to the therapeutic and diagnostic approach.

Benchmarking iron dextran sensitivity: reactions requiring resuscitative medication in incident and prevalent patients

BACKGROUND

Reliable information on the incidence of severe reactions to iron dextran is limited. Administration of agents of resuscitation in acute anaphylaxis may serve as a marker to quantify life-threatening adverse drug reactions.

METHODS

To determine the incidence of the most serious reactions to intravenous (i.v.) iron dextran, we searched the Gambro Healthcare US medical database for evidence of same-day administration of both i.v. iron dextran and parenteral adrenaline, corticosteroids or antihistamines. We confirmed each case as an iron dextran sensitivity reaction by direct inquiry. We also determined the total reported number of suspected adverse iron dextran reactions.

RESULTS

During the 16 month study period, we determined that 1,066,099 doses of i.v. iron dextran were given to 48,509 patients, including 20,213 patients who had not previously received iron dextran (iron dextran naïve). We identified seven patients who experienced reactions requiring resuscitative agents, all in response to a test dose (five patients) or first therapeutic dose (two patients), and therefore all in the iron-naïve (incident) group. Thus, we found the incidence of iron dextran reactions requiring resuscitative agents to be 0.035% (7 out of 20,213). No reaction was fatal. In a combined group of incident and prevalent patients, we found 337 total reports of suspected adverse reactions to iron dextran, without regard to severity of reaction, yielding an overall per patient adverse drug event (ADE) rate of 0.69% (337 out of 48,509) and per exposure rate of 0.03% (337 out of 1,066,099).

CONCLUSIONS

The incidence of reactions to iron dextran requiring resuscitative medications, per exposure or per patient, is approximately 0.035%. Reactions of this severity occur after either the test dose or first dose of iron dextran.

Dose-dependent effect of parenteral iron therapy on bleomycin-detectable iron in immune apheresis patients

BACKGROUND

Iron deficiency and anemia are commonly encountered in patients with autoimmune diseases undergoing immune apheresis. This makes erythropoietin and iron substitution necessary in most patients. However, intravenous iron therapy may result in an increase of potentially toxic nontransferrin-bound iron.

METHODS

We examined the effect of 50 mg or 100 mg of iron (III) sucrose on bleomycin-detectable iron (BDI) in immune apheresis patients. Six patients with autoimmune disorders and normal kidney function were enrolled. Before and after the injection of 50 mg or 100 mg of iron (III) sucrose, BDI was measured in serum samples at five different time points.

RESULTS

There was no BDI traceable before injection of iron (III) sucrose. BDI was present in serum of all patients after the administration of 100 mg of iron (III) sucrose in concentrations up to 0.49 micromol/L. In contrast, only one patient showed BDI at a concentration of 0.16 micromol/L after the administration of 50 mg of iron (III) sucrose.

CONCLUSION

We conclude that if parenteral iron is administered after apheresis treatment, despite the equal tolerability, use of 50 mg of iron (III) sucrose is superior to 100 mg of iron (III) sucrose in avoiding the formation of potentially toxic nontransferrin-bound iron.

Impairment of Transendothelial Leukocyte Migration by Iron Complexes

ABSTRACT. Although iron sucrose and iron gluconate are generally well tolerated in patients who are treated for renal anemia, recent clinical studies and cell culture experiments suggested significant toxicity and long-term side effects arising from the use of these iron complexes. Because of the possible role of iron in infection or cardiovascular disease, it was theorized that parenteral iron compounds influence endothelial and PMN interactionin vitro. A well-established double-chamber method was used to assess the effect of different concentrations of iron sucrose and iron gluconate (1, 25, 50, and 100 μg/ml) on the transendothelial migration of PMN. Preincubation of PMN and endothelial cells as well as preincubation of PMN alone with 25, 50, or 100 μg/ml iron resulted in a significant decrease in PMN migration. In contrast, after incubation of the endothelial cells alone with iron, no reduction in the transendothelial migration of PMN was observed. Preincubation of PMN and/or endothelial cells with 1 μg/ml iron did not lead to any decrease in the rate of migrated PMN. The only significant change in experiments with 1 μg/ml was an increase in PMN migration after preincubation of endothelial cells and PMN with iron gluconate. A four-way ANOVA showed a significant effect of the iron concentration (P< 0.000001), of type of iron complex (P< 0.005), of the preincubation of endothelial cell (P< 0.001), and of the preincubation of PMN with iron (P< 0.000001) on PMN diapedesis. It is concluded that iron sucrose and iron gluconate cause a significant inhibition of transendothelial migration of PMN. E-mail: Guerkan.Sengoelge@univie.ac.at

[Indications and practical management of parenteral iron therapy]

Absolute or functional iron deficiency is a common problem in chronic disease which may lead to iron-deficient erythropoesis. Moreover, lack of available iron is the most common reason for unresponsiveness to epoetin in patients on chronic dialysis. Measurements of serum ferritin, transferrin saturation and percentage of hypochromic red blood cells allow the assessment of iron status. Lack of iron resorption and dose-dependent side-effects limit oral supplementation in a number of patients. Several iron preparations are available for intravenous substitution, especially the newly registered iron-saccharose offers safe and reliable iron supplementation and reduces the risk of anaphylaxis and iron toxicity. This review discusses new guidelines concerning diagnosis of iron status, indication for therapy and application of intravenous iron preparation.

Influence of parenteral iron preparations on non-transferrin bound iron uptake, the iron regulatory protein and the expression of ferritin and the divalent metal transporter DMT-1 in HepG2 human hepatoma cells

It is widely assumed that standard parenteral iron preparations are degraded in the reticuloendothelial cells and that the iron is subsequently incorporated into transferrin. Hepatocytes or other epithelial cells have been considered as not affected. We show that this picture should be carefully reconsidered. By using the human hepatoma cell line HepG2 we showed that the parenteral iron preparations ferric saccharate and ferric gluconate donated iron to the cells as efficiently as low molecular weight iron and stimulated non-transferrin bound iron uptake. This led to inactivation of the iron regulatory protein 1 and to an increase in the expression of ferritin and of the divalent metal transporter (DMT-1). Ferric dextran was only a weak stimulator of ferritin and DMT-1 expression. The observed changes in iron metabolism occurred at concentrations of parenteral iron that can also be found in the plasma of patients after i.v. infusion. We conclude that parenteral iron also influences the iron metabolism of non-reticuloendothelial cells like HepG2 cells. Further the increase in the expression of the transporter DMT-1 in HepG2 cells after iron treatment is in contrast to the regulation in the duodenum and may be involved in the upregulated uptake of potentially toxic non-transferrin bound iron from the circulation to store it in the non-toxic form of ferritin.

A randomized, controlled parallel-group trial on efficacy and safety of iron sucrose (Venofer) vs iron gluconate (Ferrlecit) in haemodialysis patients treated with rHuEpo

BACKGROUND

The objectives of the present trial were to compare the efficacy and safety of two i.v. iron preparations with respect to haemoglobin levels, iron status and recombinant human erythropoetin (rHuEpo) dosage requirements in stable, rHuEpo-treated haemodialysis patients (maintenance phase of iron treatment) over 6 months.

METHODS

A total of 59 patients were randomized and assigned to one of two treatment groups and 55 patients were analysed (iron sucrose n=27; iron gluconate n=28). Iron sucrose was administered in a dose of 250 mg iron diluted in 100 ml normal saline given over 60 min once per month, while 62.5 mg iron as iron gluconate was given once per week in a slow push injection (5 min).

RESULTS

--Efficacy parameters: Haemoglobin levels could be maintained from baseline to endpoint in both groups. There were, however, more patients in the iron sucrose group than in the iron gluconate group for whom treatment was discontinued because their haemoglobin values exceeded 12.5 g/dl or ferritin values exceeded 1000 ng/ml (five vs two and three vs one patient, respectively). Transferrin saturation and serum ferritin increased significantly in both groups (+255.7 ng/ml with iron sucrose and +278.5 ng/ml with iron gluconate), while rHuEpo dosage did not change significantly throughout the study. --Safety parameters: There were a total of 174 infusions of iron sucrose and 720 injections of iron gluconate during the trial; all of them were well tolerated. In particular, we did not observe anaphylactoid reactions or any events suggestive of iron toxicity such as hypotension, dizziness, or nausea.

CONCLUSIONS

High doses of iron sucrose (Venofer((R)) at a dose of 250 mg/month) was equally effective in maintaining haemoglobin and equally well tolerated as low doses of iron gluconate (Ferrlecit((R)) at a dose of 62.5 mg once per week) in stable, rHuEpo treated haemodialysis patients.

Iron Sucrose Injection

Each month, subscribers to The Formulary® Monograph Service receive five to six researched monographs on drugs that are newly released or are in late Phase III trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. The monographs are published in printed form and on diskettes that allow customization. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board called The Formulary Information Exchange (The F.I.X). All topics pertinent to clinical pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The April 2001 Formulary monographsare on caspofungin, peginterferon alfa-2b, ziprasidone, 90Y ibritumomab tiuxe-tan, and Abarelix depot. The DUE is on caspofungin.

Intravenous iron dextran treatment in predialysis patients with chronic renal failure

Iron deficiency anemia is common in patients with chronic renal failure not undergoing hemodialysis. Current therapy consists of oral or intravenous (IV) iron dextran (IVID). The standard IV regimen is 100 to 200 mg/dose for a 1-g total dose. We hypothesized that 500 mg/wk of IVID for two doses would be less costly and equally effective as 200 mg/wk for five doses. We prospectively studied 22 patients with creatinine clearances less than 50 mL/min who were not undergoing dialysis and had anemia and evidence of iron deficiency (ferritin level <100 ng/mL or transferrin saturation [TSAT] <20%). Patients were randomized into two groups: group I (n = 8), 200 mg/wk of IVID for 5 weeks, and group II (n = 14), 500 mg/wk of IVID for 2 weeks. All patients tolerated IVID infusions without serious adverse reactions. Over the 6-month follow-up, both groups experienced an increase in hemoglobin levels from baseline. Ferritin levels in both groups increased (P < 0.005), peaked at 2 weeks, then declined thereafter. Over the 6-month follow-up, both groups experienced significant improvement, although the beneficial effects of group II declined at a significantly faster rate than group I (P = 0.003). There was no significant difference in change in ferritin levels between groups. TSAT peaked at 2 weeks in both groups (P < 0. 001). Group I experienced a significant increase in TSAT throughout the 6-month follow-up (P < 0.03), and group II achieved a significant increase in TSAT at 2 weeks, but not at 3 and 6 months. There was no significant difference in pretreatment to posttreatment change in TSAT. Treatment in group II was 35.2% more cost-effective than in group I ($965 versus $1,490, respectively). We conclude that IVID, 500 mg/wk, for 2 weeks is as effective and safe as 200 mg/wk for 5 weeks, but much less costly.

Erythropoietin, iron, and erythropoiesis

Recent knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with blood loss anemia, with or without recombinant human erythropoietin therapy, has implications for patient management. Under conditions of significant blood loss, erythropoietin therapy, or both, iron-restricted erythropoiesis is evident, even in the presence of storage iron and iron oral supplementation. Intravenous iron therapy in renal dialysis patients undergoing erythropoietin therapy can produce hematologic responses with serum ferritin levels up to 400 μg/L, indicating that traditional biochemical markers of storage iron in patients with anemia caused by chronic disease are unhelpful in the assessment of iron status. Newer measurements of erythrocyte and reticulocyte indices using automated counters show promise in the evaluation of iron-restricted erythropoiesis. Assays for serum erythropoietin and the transferrin receptor are valuable tools for clinical research, but their roles in routine clinical practice remain undefined. The availability of safer intravenous iron preparations allows for carefully controlled studies of their value in patients undergoing erythropoietin therapy or experiencing blood loss, or both.

Erythropoietin, iron, and erythropoiesis

Recent knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with blood loss anemia, with or without recombinant human erythropoietin therapy, has implications for patient management. Under conditions of significant blood loss, erythropoietin therapy, or both, iron-restricted erythropoiesis is evident, even in the presence of storage iron and iron oral supplementation. Intravenous iron therapy in renal dialysis patients undergoing erythropoietin therapy can produce hematologic responses with serum ferritin levels up to 400 μg/L, indicating that traditional biochemical markers of storage iron in patients with anemia caused by chronic disease are unhelpful in the assessment of iron status. Newer measurements of erythrocyte and reticulocyte indices using automated counters show promise in the evaluation of iron-restricted erythropoiesis. Assays for serum erythropoietin and the transferrin receptor are valuable tools for clinical research, but their roles in routine clinical practice remain undefined. The availability of safer intravenous iron preparations allows for carefully controlled studies of their value in patients undergoing erythropoietin therapy or experiencing blood loss, or both.

Parenteral iron use in the management of anemia in end-stage renal disease patients

Intravenous iron is required by most dialysis patients receiving erythropoietin (EPO) to maintain an adequate hematocrit. In the United States, there are currently two parenteral iron preparations, iron dextran and iron gluconate, approved for such use, and a third product, iron sucrose, is under development. This article reviews each of these products. Each of the iron products increases the efficacy of EPO use in anemia management. There is considerable experience in the United States and elsewhere with the use of iron dextran. Although it is clinically effective, iron dextran is also associated with significant morbidity from both dose-dependent and -independent side effects. The slow release of iron from this complex necessitates a delay in monitoring iron indices after the administration of large doses of iron dextran. Recommended doses of iron sucrose appear very safe with little risk of anaphylactic reactions. Adverse effects are uncommon and not life threatening. If approved for use in the United States, iron sucrose may be a safe and effective alternative to iron dextran. Iron dissociates from iron gluconate quite rapidly and may increase the production of ionized free iron. Iron gluconate may be a safe alternative to iron dextran for patients with severe reactions, including anaphylaxis. The risk of allergic reactions to iron gluconate is very low. The exact place in therapy for the newer iron complexes remains unclear. Currently available data suggest that iron sucrose and iron gluconate may have diminished adverse effect profiles when compared with iron dextran. Additional clinical experience will establish the role for these new iron products.

Sodium Ferric Gluconate Complex in Sucrose Injection

Each month, subscribers to The Formulary® Monograph Service receive five to six researched monographs on drugs that are newly released or are in late Phase III trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. The monographs are published in printed form and on diskettes that allow customization. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board called The Formulary Information Exchange (The F.I.X). All topics pertinent to clinical pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The August 1999 Formulary monographs are on rofecoxib/celecoxib, rosiglitazone, rivastigmine, doxercalciferol, oseltamivir. The DUE is on rosiglitazone.