A Retrospective Case Review of Adverse Drug Reactions Using Intravenous Iron in Non-Hemodialysis Patients.

Background:

Intravenous iron therapy is commonly used in hemodialysis patients but has not been well studied in other patient populations. Intravenous iron has many documented adverse drug reactions and the types and incidence of reactions differ based on the type of intravenous iron therapy used. In Canada, two forms of iron therapy are currently being used: Iron dextran marketed as Infufer or DexIron and iron sucrose marketed as Venofer are available. The general consensus in the literature is that the incidence of serious adverse reactions is relatively low approximately 0.6–0.7% with intravenous iron dextran. The objective of this retrospective chart review was to observe recorded adverse events of iron dextran (Infufer) and iron sucrose (Venofer) in our own non-hemodialysis patients.

Methods:

240 non-hemodialysis adult outpatient charts were reviewed. Iron dextran (Infufer) or iron sucrose (Venofer) infusions were recorded from July 20, 2000 to July 13, 2004. For each chart, the patient age, sex, date of birth, past medical history, medications and allergies were recorded. The type of intravenous iron, if premedication was used, and a description of any reaction if it occurred was also recorded. Each adverse reaction was graded on causality, severity, and system classification based on WHO standards done by two investigators virtually blinded to the type of iron therapy used.

Results:

Of the 240 patient charts reviewed, there were a total of 403 intravenous iron infusions given within the study period. The age of the patients ranged from 19 to 91 with mean age 60.3 +/− 16.3. The majority of our patients were end-stage renal disease peritoneal dialysis patients 187 (78%). 11 (5%) had a history of connective tissue disease or vasculitis, 15 (6%) had a history of asthma, and 84 (35%) used an angiotension converting enzyme inhibitor (ACEI). Only 17 patients (38 total infusions) received premedication.

The total number of adverse events of all descriptions was 103 (26%) of the 403 total intravenous iron infusions. This was equally distributed to males 40 out of 156 (26%) and females 63 out of 247 (26%). Of the 365 intravenous therapies not given premedication there were 89 (24%) adverse events. The total number of "certain severe allergic" reactions (CSAs) was 25/403 (6%). In iron dextran (Infufer) a total of 77/295 (26%) ADRs were noted and CSAs of 23/295 (8%). In iron sucrose (Venofer) there was a total of 26/105 (25%) ADRs and 2/105 (2%) CSAs.

Of the 295 intravenous iron dextran infusions, 209 had a test dose given. Of these 209, there were 60 ADRs - 25 during the test dose (12%) and 35 (17%) after the test dose.

Conclusions:

Adverse events and CSAs in our adult outpatient non-hemodialysis patients receiving intravenous iron therapy with either iron dextran (Infufer) and iron sucrose (Venofer) are much higher than previously reported in the literature. There are more ADRs and CSAs in the iron dextran group than the iron sucrose group. Premedication did not appear to reduce ADRs. Having a normal test dose did not preclude to getting ADRs afterwards.