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

Abstract

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; ISS_FRX) 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 (IS_ORIG), ISS_FRX diluted in 100 mL saline and ISS_FRX 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 IS_ORG group and 210 and 279 in the ISS_FRX-100 and ISS_FRX-200 groups respectively. Adverse drug reactions were more frequent in the ISS_FRX groups vs. IS_ORIG (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 ISS_FRX 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.

Keywords::

• Adverse drug reaction
• Anemia, iron-deficiency
• Gynecology
• Iron sucrose
• Similar

Transparency

Declaration of funding

Funding to permit data collection and retrospective analysis was provided by JW Pharmaceuticals and ViforPharma Ltd (Switzerland). All dosing and patient treatment decisions were made prior to any funding, hence not influencing treatment choice. Additionally, all analysis was completed independently of the funding companies without any stipulation on content of manuscript.

Declaration of financial/other relationships

All authors have no interests which might be perceived as posing a conflict or bias.

Acknowledgments

The authors acknowledge the support of the Vifor (International) Ltd, the Quality Control division in St Gallen, Switzerland for their physicochemical analysis of the iron sucrose similar product, Ferex and editorial support with the completion of this manuscript.