Can Feraheme 510mg Be Given Six Days Apart?
Yes, Feraheme (ferumoxytol) 510mg can be administered six days apart, as this falls within the FDA-approved dosing interval of 3 to 8 days between doses. 1
FDA-Approved Dosing Schedule
The official FDA labeling for ferumoxytol specifies:
- Initial dose: 510 mg intravenously
- Second dose: 510 mg given 3 to 8 days after the first dose 1
- Each dose should be administered as an infusion over at least 15 minutes 1
Since six days falls squarely within the 3-8 day window, this dosing interval is completely appropriate and FDA-approved.
Evolution of Dosing Recommendations
The current dosing schedule represents an important safety evolution:
- Original approval: The drug was initially approved for rapid injection (510 mg in 17 seconds), which led to a high incidence of infusion reactions that were often misinterpreted as anaphylaxis 2
- Revised labeling: The FDA subsequently changed the label to require infusion over at least 15 minutes in two divided doses given 1 week apart (which was later expanded to 3-8 days) 2
- Current safety profile: Using the slower infusion method, serious adverse events are "vanishingly rare" with minor infusion reactions occurring at only 1-3% incidence, equivalent to other IV iron formulations 2
Alternative Dosing Considerations
While the two-dose regimen remains the official FDA labeling, expert consensus guidelines note:
- Single-dose option: Multiple studies have demonstrated safety and efficacy of administering 1020 mg (two vials) as a single 30-minute infusion without any serious adverse events 2
- Insurance considerations: The single-dose approach may be used "insurance permitting" 2
- Administration technique: When using either approach, start the infusion slowly and observe for several minutes before completing the infusion 2
Important Clinical Caveats
MRI interference: Ferumoxytol is a superparamagnetic iron oxide that can affect MRI interpretation for up to 3 months after administration—radiologists must be notified if MRI is planned within this timeframe 2, 3
Generic formulation concerns: The ferumoxytol generic approved in 2022 has shown double the incidence of infusion reactions compared to brand name, with one death reported in FDA filing data—exercise caution with generic substitution 2
Monitoring timeline: Evaluate hematologic response (hemoglobin, ferritin, iron, and transferrin saturation) at least one month following the second infusion 1