Is intravenous iron therapy with Feraheme (ferumoxytol) medically necessary for a patient with iron deficiency anemia secondary to chronic blood loss, who has a history of pulmonary embolism and cannot tolerate oral iron due to constipation?

Intravenous Feraheme is NOT medically necessary for this patient without documented iron deficiency anemia and without attempting oral iron therapy first.

Critical Missing Documentation

The fundamental problem is that iron deficiency anemia has never been confirmed in this patient. 1

• Laboratory results ordered on the specified date (CBC with differential, ferritin, iron, TIBC, BMP) were never obtained or documented 1
• The American Society of Hematology requires either serum ferritin <30 ng/mL OR transferrin saturation <20% to diagnose iron deficiency anemia 1
• Without these baseline iron studies, it is impossible to confirm IDA, determine appropriate iron dosing, monitor response to therapy, or avoid potential iron overload 1

Oral Iron Must Be Attempted First

Current AGA guidelines from 2024 are unequivocal: oral iron is first-line therapy for iron deficiency anemia. 2

• The American Gastroenterological Association recommends oral iron as first-line treatment for patients with iron deficiency anemia who have not been previously intolerant to oral iron 1
• Concern about constipation is NOT a contraindication to oral iron—it is merely a potential side effect 1
• Multiple GI-friendly oral iron strategies exist that minimize constipation risk 1:
  • Alternate-day dosing reduces hepcidin elevation, improves absorption, and decreases GI side effects 1
  • Lower elemental iron doses (25-50 mg daily) significantly reduce GI side effects 1
  • Ferrous bisglycinate or polysaccharide-iron complex provide better GI tolerability 1
  • Liquid formulations can minimize constipation 1

When IV Iron Is Appropriate

The 2024 AGA Clinical Practice Update clearly defines when intravenous iron should be used: 2

Intravenous iron is appropriate for patients with:

• Documented unsatisfactory response to oral iron (not just anticipated intolerance) 2, 1
• Documented intolerance to oral iron after an actual trial 2, 1
• Malabsorption conditions such as inflammatory bowel disease with active inflammation, celiac disease with severe villous atrophy, or post-bariatric surgery 2
• Blood loss exceeding the ability to replete iron orally 2

Specific Concerns with This Case

This patient has heavy uterine bleeding as the likely etiology, which typically responds well to oral iron: 2

• The AGA 2020 guidelines note that oral iron supplementation is generally effective, available, inexpensive, and safe for most patients 2
• A response to oral iron (with improvements in hemoglobin) is typically evident within 1 month of treatment 2
• Heavy uterine bleeding alone does not automatically qualify for IV iron unless blood loss exceeds oral replacement capacity, which has not been documented 2

The patient is actively trying to conceive, making proper documentation even more critical: 3

• Ferumoxytol is superparamagnetic iron oxide that interferes with MRI interpretation for up to 6 months after administration 1, 3
• This could complicate prenatal imaging if pregnancy occurs 3

Recommended Clinical Pathway

Before any IV iron can be considered medically necessary, the following steps must occur:

1. Obtain the ordered iron studies (ferritin, iron, TIBC, transferrin saturation) to confirm iron deficiency anemia 1
2. Initiate a trial of oral iron using GI-friendly strategies such as ferrous bisglycinate 25-50 mg on alternate days 1
3. Reassess hemoglobin and iron parameters in 4 weeks to document response or lack thereof 2, 1
4. Only after documented failure of oral iron (no improvement in hemoglobin or iron parameters after 1 month) should IV iron be considered 2, 1

Common Pitfalls to Avoid

• Do not skip oral iron trials based solely on patient preference or anticipated side effects 1
• Do not assume constipation makes oral iron impossible—multiple formulations and dosing strategies exist 1
• Do not administer IV iron without baseline iron studies, as this prevents proper monitoring and risks iron overload 1
• Remember that ferumoxytol requires at least 15 minutes infusion time and can cause serious hypersensitivity reactions 3, 4

The peer-to-peer discussion should focus on obtaining the missing laboratory documentation and initiating an appropriate oral iron trial with alternate-day dosing of ferrous bisglycinate 25-50 mg to minimize constipation risk. 1