Iron Injectables

At bottom of post, more information on COVID-19.

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At a recent Pharmacy, Nutrition, and Therapeutics (PNT) meeting, one of the topics that we reviewed was injectable iron agents, primarily iron sucrose (Venofer ®) and ferric carboxymaltose (Injectafer®).  Iron dextran is mainly used as a supplement in parenteral nutrition in our patient population.

Also, this topic is reviewed in Practical Gastroenterology Jan 2020 (M Auerbach et al. January 2020 • Volume XLIV, Issue 1: Treatment of Iron Deficiency in Gastroenterology: A New Paradigm

Key points:

  • Venofer® is much less expensive and currently has an FDA indication for children. To provide 1500 mg, Venofer®, 5 doses of 300 mg (~$75/dose)~$375. Injectafer®, 2 doses of 750 mg (~$600/dose) ~1200.  This does not include potential travel and other ancillary costs.
  • Dosing: Injectafer® can give large amounts of iron; in adults, typical dose is 750 mg given 7 days apart (in children 15 mg/kg/dose with 750 mg max).  FDA approved method is to administer over 15 minutes. Venofer® in children is 5-7 mg/kg/dose with 300 mg max per dose.
  • Injectafer® has been associated with hypophosphatemia (in 27%, <2 mg/dL); Hypophosphatemia has also been reported with iron sucrose.  The reported incidence of hypophosphatemia is higher with ferric carboxymaltose vs iron sucrose.
  • Other Adverse Effects
Iron Sucrose (Venofer®) Ferric Carboxy (Injectafer®)
Nausea 8.6% 7.2%
Vomiting 5% 1.7%
Diarrhea 7.2% <1%
Dizziness 6.5% 2%
Hypertension 6.5% 3.8%

Oral vs IV Iron for IBD: Auerbach et al recommends that “iron should only be given orally to IBD patients with inactive disease, mild anemia, and good tolerance of oral iron; in patients with active IBD oral iron should be avoided.”  They state that “oral iron has been shown to exacerbate intestinal inflammation of IBD independent of anemia, and cause luminal changes in microbiota and bacterial metabolism, which may negatively alter the microbiome.” (Has IV iron’s effect on the microbiome been studied/compared to oral iron?)

Safety of intravenous iron: “In a recent meta-analysis, the results of more than 10,000 patients who were treated with intravenous iron were reported. Compared to oral iron, placebo, and even intramuscular iron (which should never be given), while minor infusion reactions were observed with IV iron, there was no increase in serious adverse events compared to any comparator including placebo.”

My take: Injectafer® is likely preferable to Venofer® in the outpatient setting as adequate dosing can be given in 1 or 2 infusions.

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Here’s a link to Financial Times COVID-19 Tracker –includes logrithmic charts plotting the rates of reported infection and deaths and allows quick comparison between countries and high-volume locations (eg. Madrid, Lombardia, NY City).  Some figures from March 23, 2100 GMT noted below; unfortunately, the U.S is likely to the world leader in number of reported cases quite soon.

Other relevant tweets:

 

Microcytic Anemia Review

A useful review of microcytic anemia (NEJM 2014; 371: 1324-31) discusses the most common causes, mechanisms and treatment of microcytic anemia.

Common causes discussed include thalassemia, iron deficiency anemia, and anemia of inflammation.  With the latter, the authors review the pathophysiology: “the cause of this anemia is twofold. First, renal production of erythropoietin is suppressed by inflammatory cytokines, resulting in decreased red-cell production. Second, lack of iron availability for developing red cells can lead to microcytosis.  The lack of iron is largely due to the protein hepcidin, an acute-phase reactant that leads to both reduced iron absorption and reduced release of iron from body stores.

Treatment of iron deficiency anemia –pointers:

  • Ferrous sulfate (325 mg [65 mg of elemental iron] orally three times a day -considered first line for adults.  Ferrous gluconate at a daily dose of 325 mg [35 mg elemental] is an alternative.
  • “Several trials suggest that lower doses of iron, such as 15 to 20 mg of elemental iron daily can be as effective as higher doses and have fewer side effects.”
  • “There are many oral iron preparations, but no one compound appears to be superior to another.”
  • In those with an inadequate response to oral iron therapy, parenteral iron can be helpful.  The authors note that low-molecular-weight iron dextran (INFeD) is “associated with an incidence of reactions that is similar to that with the newer products but allows for higher doses of iron replacement.”  Typical dosing for adults: 25 mg test dose, and if tolerated for 1 hr, can give 975 mg (1000 mg total) over 4-6 hours.  The low-molecular-weight iron dextran should not be used in patients with previous iron dextran hypersensitivity reactions.
  • Alternative IV iron products: Ferric gluconate [Ferrlecit] 125 mg adult dose over 1 hour -given weekly (8 doses = 1000 mg) or Iron Sucrose [Venofer] 200 mg adult dose over 15-60 min, 300 mg over 1.5 hr, or 500 mg over 4 hr; can repeat in subsequent sessions until total dose of 1000 mg.

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Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.