Comparison of adverse event profile of intravenous iron sucrose and iron sucrose similar in postpartum and gynecologic operative patients

Objective Severe iron deficiency resulting in anemia is a common problem during pregnancy and in menstruating women. Several choices for IV iron replacement therapies exist and increased pressures on budgets may require cheaper 'iron sucrose similar' (ISS) to be used. In our practice, an iron sucrose similar (Ferex; ISSFRX) was introduced to reduce costs in the treatment of pregnant women or those planned for surgery. Post several months of use we observed increased rates of adverse events from patients and hence performed this analysis to confirm these findings. Methods Data on adverse events was retrospectively collected from 658 patients treated between September 2004 and December 2011. Patients were analyzed in three cohorts, iron sucrose originator (ISORIG), ISSFRX diluted in 100 mL saline and ISSFRX diluted in 200 mL saline. Results The mean age was 38.5 years and included patients having normal delivery, Cesarean section, myomectomy, hysterectomy, cystectomy and adnexectomy. There were 169 patients in the ISORG group and 210 and 279 in the ISSFRX-100 and ISSFRX-200 groups respectively. Adverse drug reactions were more frequent in the ISSFRX groups vs. ISORIG (11.0 vs. 14.3 vs. 1.8%; p<0.02). Events were mild-to-moderate in nature and were predominately injection site reactions and phlebitis. Results may be impacted by imbalance in baseline characteristics and cumulative iron dose received, however events were mostly acute and all patients received 200 mg iron as single administration. Conclusion This is the first large analysis suggesting increased adverse events due to an ISS. For our practice, the use of ISSFRX was discontinued owing to safety concerns outweighing the theoretical cost benefit. This study raises the question on the appropriate approval process for complex drugs and if these can be substituted without appropriate clinical testing, both for efficacy and most importantly safety, in routine clinical practice.