Is intramuscular (IM) iron injection safe to treat iron deficiency anemia in patients with thrombocytosis?

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Last updated: June 13, 2025View editorial policy

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From the Research

Intramuscular (IM) iron injections are not recommended for treating iron deficiency anemia in patients with thrombocytosis due to safety concerns and unpredictable absorption, and instead, intravenous (IV) iron formulations should be used as the preferred treatment approach. The use of IM iron preparations like iron dextran or iron sorbitol can cause significant local pain, staining of the skin, sterile abscesses, and tissue necrosis at injection sites, as well as unpredictable absorption, especially in patients with thrombocytosis where altered blood flow dynamics may further compromise absorption 1, 2.

Key Considerations

  • For patients with thrombocytosis and iron deficiency anemia, IV iron allows for more predictable dosing, better tolerability, and avoids the complications associated with IM administration.
  • The typical IV iron regimen involves calculating the total iron deficit based on hemoglobin levels and body weight, then administering divided doses according to the specific IV iron product's guidelines.
  • Oral iron supplements may be considered for mild cases, but absorption is often suboptimal, particularly in the presence of inflammation, which can upregulate hepcidin and limit iron absorption 2.
  • The underlying thrombocytosis should also be investigated and addressed, as it may be reactive to the anemia or indicate a myeloproliferative disorder requiring specific management 1, 3.

Treatment Approach

  • IV iron formulations such as iron sucrose, ferric carboxymaltose, or iron dextran are preferred for treating iron deficiency anemia in patients with thrombocytosis.
  • Modern parenteral iron formulations have substantially altered iron treatment and enable rapid, safe total-dose iron replacement 2.
  • An underlying cause should be sought in all patients presenting with iron deficiency, including screening for coeliac disease and endoscopic investigation to exclude bleeding gastrointestinal lesions 2.

Recent Evidence

  • A recent study published in 2020 found that intravenous ferric carboxymaltose is a safe and effective treatment option for the management of cancer-induced anemia, with significant increments in hemoglobin levels observed in patients with absolute and functional iron deficiency 4.
  • Another study published in 2021 highlighted the importance of addressing iron deficiency, which is one of the leading contributors to the global burden of disease, and emphasized the role of modern parenteral iron formulations in enabling rapid and safe total-dose iron replacement 2.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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