On the relative safety of parenteral iron formulations

The safety and efficacy of ferumoxytol therapy in anemic chronic kidney disease patients

BACKGROUND

Administration of safe and effective iron therapy in patients with chronic kidney disease is a time consuming process. This phase II clinical trial studied ferumoxytol, a semi-synthetic carbohydrate-coated iron oxide administered by rapid intravenous injection to anemic chronic kidney disease patients (predialysis or undergoing peritoneal dialysis).

METHODS

Inclusion criteria included hemoglobin < or =12.5 g/dL and transferrin saturation < or =35%. Twenty-one adult patients were randomized to receive ferumoxytol in a regimen of 4 doses of 255 mg iron in 2 weeks or 2 doses of 510 mg iron in 1 to 2 weeks. Ferumoxytol was administered at a rate of up to 30 mg iron/sec.

RESULTS

The maximum hemoglobin response following ferumoxytol administration occurred at 6 weeks, increasing from a baseline of 10.4 +/- 1.3 g/dL to 11.4 +/- 1.2 g/dL (P < 0.05). Ferritin increased from a baseline of 232 +/- 216 ng/mL to a maximum of 931 +/- 361 ng/mL at 2 weeks (P < 0.05), while the baseline transferrin saturation increased from 21 +/- 10% to 37 +/- 22% at 1 week (P < 0.05). Seven adverse events in 5 patients during this trial were deemed possibly related to ferumoxytol, none serious. These events included constipation, chills, tingling, a gastrointestinal viral syndrome, delayed pruritic erythematous rash, and transient pain at the injection site.

CONCLUSION

Although larger studies are required, this small study demonstrates that ferumoxytol can be safe and effective in increasing iron stores, is associated with an increased hemoglobin response, and is well tolerated at a rapid infusion rate.

Acute Hypersensitivity Reaction to Ferric Gluconate in a Premedicated Patient

OBJECTIVE

To report a case of an acute hypersensitivity reaction to ferric gluconate in a patient premedicated with dexamethasone, diphenhydramine, and prochlorperazine.

CASE SUMMARY

A 38-year-old female with persistent iron deficiency anemia was initiated on parenteral iron therapy with ferric gluconate 125 mg intravenously over 10 minutes. The patient initially tolerated this first dose well; however, she later experienced nausea, dizziness, and minor tongue swelling. On her second course of therapy, the woman was premedicated with dexamethasone, diphenhydramine, and prochlorperazine prior to the same dose of ferric gluconate infused over 30 minutes. Subsequently, the patient developed epigastric pain, nausea, swelling of her lips and tongue, and hypotension. The symptoms abated after administration of diphenhydramine, dexamethasone, morphine, cimetidine, intravenous fluids, and oxygen. She was discharged after a short stay in the emergency department observation unit.

DISCUSSION

Data are limited on the relative safety of ferric gluconate compared with iron dextran. Ferric gluconate does not appear to be associated with severe life-threatening events; however, the possibility of an acute hypersensitivity reaction with this product does exist. In this case, use of the Naranjo probability scale indicated a probable relationship between the hypersensitivity reaction and ferric gluconate.

CONCLUSIONS

Healthcare professionals should be aware of this serious but rare event and encouraged to further document and report these events.

Update on adverse drug events associated with parenteral iron

BACKGROUND

We previously compared the safety profile of three formulations of intravenous iron used during 1998-2000 and found higher rates of adverse drug events (ADEs) associated with the use of higher molecular weight iron dextran and sodium ferric gluconate complex compared with lower molecular weight iron dextran. Since that time, iron sucrose has become widely available and clinicians have gained additional experience with sodium ferric gluconate complex.

METHODS

We obtained data from the United States Food and Drug Administration (FDA) on ADEs attributed to the provision of four formulations of intravenous iron during 2001-2003, including higher and lower molecular weight iron dextran, sodium ferric gluconate complex and iron sucrose. We estimated the odds of intravenous iron-related ADEs using 2 x 2 tables and the chi(2) test.

RESULTS

The total number of reported parenteral iron-related ADEs was 1141 among approximately 30,063,800 doses administered, yielding a rate of 3.8 x 10(-5), or roughly 38 per million. Eleven individuals died in association with the ADE. Relative to lower molecular weight iron dextran, total and life-threatening ADEs were significantly more frequent among recipients of higher molecular weight iron dextran and significantly less frequent among recipients of sodium ferric gluconate complex and iron sucrose. The absolute rates of life-threatening ADEs were 0.6, 0.9, 3.3 and 11.3 per million for iron sucrose, sodium ferric gluconate complex, lower molecular weight iron dextran and higher molecular weight iron dextran, respectively. Based on differences in the average wholesale price of iron sucrose and lower molecular weight iron dextran in the US, the cost to prevent one life-threatening ADE related to the use of lower molecular weight iron dextran was estimated to be 5.0-7.8 million dollars. The cost to prevent one lower molecular weight iron dextran-related death was estimated to be 33 million dollars.

CONCLUSIONS

The frequency of intravenous iron-related ADEs reported to the FDA has decreased, and overall, the rates are extremely low. This is the fourth report suggesting increased risks associated with the provision of higher molecular weight iron dextran. Life-threatening and other ADEs appear to be lower with the use of non-dextran iron formulations, although the cost per ADE prevented is extremely high.

Hypersensitivity reactions and deaths associated with intravenous iron preparations

BACKGROUND

Parenteral iron therapy is an accepted adjunctive management of anaemia in kidney disease. Newer agents may have fewer severe hypersensitivity adverse events (AE) compared with iron dextrans (ID). The rate of type 1 AE to iron sucrose (IS) and sodium ferric gluconate (SFG) relative to ID is unclear. We used the US Food and Drug Administration's Freedom of Information (FOI) surveillance database to compare the type 1 AE profiles for the three intravenous iron preparations available in the United States.

METHODS

We tabulated reports received by the FOI database between January 1997 and September 2002, and calculated 100 mg dose equivalents for the treated population for each agent. We developed four clinical categories describing hypersensitivity AE (anaphylaxis, anaphylactoid reaction, urticaria and angioedema) and an algorithm describing anaphylaxis, for specific analyses.

RESULTS

All-event reporting rates were 29.2, 10.5 and 4.2 reports/million 100 mg dose equivalents, while all-fatal-event reporting rates were 1.4, 0.6 and 0.0 reports/million 100 mg dose equivalents for ID, SFG and IS, respectively. ID had the highest reporting rates in all four clinical categories and the anaphylaxis algorithm. SFG had intermediate reporting rates for urticaria, anaphylactoid reaction and the anaphylaxis algorithm, and a zero reporting rate for the anaphylaxis clinical category. IS had either the lowest or a zero reporting rate in all clinical categories/algorithm.

CONCLUSIONS

These findings confirm a higher risk for AE, especially serious type 1 reactions, with ID therapy than with newer intravenous iron products and also suggest that IS carries the lowest risk for hypersensitivity reactions.

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.