What is the risk of hypotension with intravenous iron infusion?

From the Guidelines

Iron infusions can cause a drop in blood pressure, particularly during or shortly after administration, but the risk is relatively low with newer formulations and can be minimized by administering the infusions slowly and following manufacturer guidelines. The risk of hypotension is higher with certain iron formulations, especially older ones like iron dextran, which has a higher rate of hypersensitivity reactions 1. Newer formulations such as ferric carboxymaltose (Injectafer), iron sucrose (Venofer), and ferumoxytol (Feraheme) generally have lower risks of severe hypotension 1.

To minimize this risk, healthcare providers should:

• Administer iron infusions slowly, following manufacturer guidelines for specific products
• Monitor patients for signs of hypotension during and after infusion, including dizziness, lightheadedness, or syncope
• Be cautious when administering iron infusions to patients with cardiovascular disease, history of hypotension, or previous reactions to iron infusions
• Consider using formulations that can replace iron deficits with 1 to 2 infusions, as they are preferred due to their convenience and similar risks 1

The mechanism behind iron-induced hypotension involves both direct vasodilatory effects and potential immune-mediated reactions, particularly with older iron formulations 1. However, life-threatening infusion reactions are extremely rare, and concern for their occurrence should not be a barrier to the use of IV iron 1.

In terms of specific administration guidelines, iron sucrose is typically given at 100-200 mg per infusion over 15-60 minutes, while ferric carboxymaltose can be administered at higher doses (up to 750-1000 mg) but should still be given over at least 15 minutes 1. Patients who experience mild reactions can be managed by stopping the infusion and restarting at a slower rate, while more severe reactions may require corticosteroids 1.

From the FDA Drug Label

Fetal/Neonatal adverse reactions Severe adverse reactions including circulatory failure (severe hypotension, shock including in the context of anaphylactic reaction) may occur in pregnant women with parenteral iron products (such as Venofer) which may cause fetal bradycardia, especially during the second and third trimester

The risk of blood pressure drop with iron infusion is associated with severe hypotension and circulatory failure, which may occur in pregnant women, especially during the second and third trimester.

• Severe adverse reactions including circulatory failure and severe hypotension may cause fetal bradycardia. 2

From the Research

Risk of Blood Pressure Drop with Iron Infusion

• The risk of blood pressure drop with iron infusion is a concern in patients undergoing hemodialysis or those with chronic kidney disease.
• A study published in 2004 3 found that the drop in blood pressure from the beginning to the end of hemodialysis was more pronounced when iron was not administered, suggesting that intravenous iron may reduce the incidence and magnitude of post-dialytic hypotension.
• Another study published in 2023 4 found that higher doses of iron sucrose were associated with a lower rate of intradialytic hypotension, but also with a higher risk of intradialytic hypertension.
• A study published in 2003 5 found that blood pressure rose slightly, but not significantly, throughout the iron sucrose infusions, and altering the infusion rate was not necessary.

Factors Influencing Blood Pressure Response

• The type of iron formulation used may influence the risk of blood pressure drop, with iron sucrose being associated with a higher rate of adverse events compared to other formulations 6.
• The dose of iron sucrose administered may also play a role, with higher doses being associated with a lower risk of intradialytic hypotension but a higher risk of intradialytic hypertension 4.
• Patient characteristics, such as the presence of diabetes or the use of erythropoiesis-stimulating agents, may also influence the blood pressure response to iron infusion 4.

Clinical Implications

• The administration of intravenous iron sucrose during hemodialysis may be associated with a lower risk of intradialytic hypotension, but also with a higher risk of intradialytic hypertension 4.
• Clinicians should carefully monitor blood pressure in patients receiving iron infusions, particularly those with a history of hypertension or hypotension.
• Further studies are needed to fully understand the mechanisms underlying the associations between iron sucrose administration and blood pressure changes during hemodialysis 4.