What Injections Do You Get for Low Iron? A Guide to Intravenous Iron Therapy

October 11, 2025 •

5 min read

Approximately 1.5 billion people worldwide suffer from iron deficiency anemia. If oral supplements are ineffective or not tolerated, your doctor may prescribe intravenous iron, prompting the question: What injections do you get for low iron?

Quick Summary

Intravenous iron therapy uses injections, such as ferric carboxymaltose (Injectafer), iron sucrose (Venofer), and ferumoxytol (Feraheme), to treat low iron levels when oral iron isn't viable or effective.

Key Points

Intravenous (IV) iron bypasses oral limitations: IV injections are necessary when oral iron supplements are ineffective, not tolerated, or when rapid iron repletion is required, as with certain pregnancies or pre-surgery.
Common IV iron options exist: Ferric carboxymaltose (Injectafer), iron sucrose (Venofer), and ferumoxytol (Feraheme) are frequently used, each differing in dosing, administration, and risk profile.
Safety monitoring is crucial: Patients receiving IV iron infusions are closely monitored for at least 30 minutes after the infusion due to the risk of hypersensitivity reactions, which, though rare with newer agents, can be severe.
Specific conditions indicate IV use: Patients with chronic kidney disease, inflammatory bowel disease, or a history of bariatric surgery are often prime candidates for IV iron due to poor oral absorption.
High-dose, rapid infusions are possible: Newer formulations like Injectafer and Feraheme allow for complete iron repletion in one or two short sessions, improving patient convenience compared to older methods.
Hypophosphatemia is a risk with some injections: Repeated use of ferric carboxymaltose (Injectafer) has been associated with a risk of developing symptomatic hypophosphatemia, which can lead to bone issues.

Understanding Intravenous Iron Injections

For many individuals with iron deficiency or iron deficiency anemia (IDA), oral iron supplements are the first line of treatment. However, some people are unable to take oral iron due to side effects like gastrointestinal upset, or have conditions that impair iron absorption, such as inflammatory bowel disease (IBD) or celiac disease. In cases of severe iron deficiency, rapid repletion is needed, which oral supplements cannot provide. In these situations, healthcare providers turn to parenteral, or intravenous (IV), iron therapy to deliver the mineral directly into the bloodstream.

Types of Intravenous Iron Injections

Several formulations of injectable iron are available, each with unique characteristics related to dosing, administration time, and side effect profiles. These modern preparations are generally considered safer and more effective than older versions, like high-molecular-weight iron dextran, which had a higher risk of severe allergic reactions.

Ferric Carboxymaltose (Injectafer)

Ferric carboxymaltose is a complex iron replacement product indicated for IDA in adults and children over 1 year of age who are intolerant to oral iron or have had an unsatisfactory response to it. It is also used for IDA in non-dialysis dependent chronic kidney disease (CKD) patients.

Dosing: Dosage is determined by a healthcare professional based on individual needs.
Administration: Administered intravenously over a specific period, typically a minimum of 15 minutes.
Side Effects: Common side effects include nausea, headache, and dizziness. A notable side effect is symptomatic hypophosphatemia (low phosphate levels), particularly with repeated treatments.

Iron Sucrose (Venofer)

Iron sucrose has been an established treatment for IDA for over two decades, particularly in patients with CKD, including those on dialysis. It is known for having a favorable safety profile with a lower risk of severe allergic reactions compared to older iron formulations.

Dosing: Administered in smaller, more frequent doses as determined by a healthcare provider.
Administration: Administered as a slow IV injection over a specified time or infused over a period ranging from 15 to 60 minutes.
Side Effects: Common side effects include headache, dizziness, nausea, and changes in taste. Rare hypersensitivity reactions and hypotension can occur.

Ferumoxytol (Feraheme)

Feraheme is a rapid iron replacement product approved for IDA in adults with CKD or in those who have had an unsatisfactory response to oral iron. It uses a carbohydrate shell to bind elemental iron, allowing for a swift administration time.

Dosing: Typically given in multiple doses separated by a few days.
Administration: Infused over a period of 15 minutes.
Side Effects: Common side effects include diarrhea, nausea, dizziness, and headache. A black box warning exists for potentially life-threatening allergic reactions, so patients are monitored closely during and after administration. It can also interfere with MRI scans for up to three months after the last dose.

Iron Dextran (INFeD)

Iron dextran is one of the older injectable iron formulations. Because it carries a higher risk of severe hypersensitivity reactions, a small test dose is typically administered before the full dose.

Dosing: The total dose is calculated by a healthcare professional based on body weight and iron levels, often given as a series of injections.
Administration: Can be given via intramuscular (IM) injection into the buttocks or as an IV infusion.
Side Effects: A higher risk of allergic reactions compared to newer formulations, along with potential delayed flu-like symptoms.

Comparison of IV Iron Injections


Feature	Ferric Carboxymaltose (Injectafer)	Iron Sucrose (Venofer)	Ferumoxytol (Feraheme)	Iron Dextran (INFeD)
Dosing Schedule	Few doses over a period of time	Multiple smaller doses	Multiple doses over a few days	Multiple doses based on calculation
Infusion Time	Approx. 15 minutes	15-60 minutes	Approx. 15 minutes	Approx. 1 hour (for full dose)
Allergy Risk	Low risk	Low risk	Potential for life-threatening reactions	Higher risk; requires test dose
Key Side Effects	Hypophosphatemia	Hypotension, dizziness	MRI interference	Delayed flu-like symptoms
Indications	IDA, CKD (non-dialysis)	IDA, CKD (dialysis and non-dialysis)	IDA, CKD	IDA (for oral intolerance)

The Intravenous Iron Infusion Process

Receiving an IV iron infusion is a straightforward procedure conducted in a hospital or clinic setting. The overall process includes:

Preparation: The healthcare provider will confirm your identity and the prescribed medication. They will clean the area where the IV will be inserted, typically in your arm or hand.
IV Insertion: A small needle with a plastic catheter is inserted into a vein and taped securely.
Infusion: The iron solution, often mixed in a saline bag, is slowly administered into the vein via the IV line. The duration depends on the specific medication, ranging from 15 minutes to over an hour.
Monitoring: You will be monitored throughout the infusion and for at least 30 minutes afterward to watch for any adverse reactions. Your vital signs, including blood pressure, will be checked.
Recovery: Once the infusion is complete, the IV is removed. You can typically resume normal activities shortly after, though you should follow any specific instructions from your provider.

Potential Side Effects and Risks of IV Iron

While generally safe, IV iron infusions can cause side effects. Awareness of these is important for a patient considering or undergoing treatment.

Hypersensitivity Reactions: Though rare with modern agents, serious, life-threatening allergic reactions (anaphylaxis) can occur. Milder hypersensitivity symptoms include flushing, itching, or hives.
Hypotension: Low blood pressure can occur, especially if the infusion is administered too quickly. Monitoring during and after the infusion helps mitigate this risk.
Hypophosphatemia: Some formulations, notably ferric carboxymaltose (Injectafer), carry a risk of causing low blood phosphate levels. Repeat treatments increase this risk, which can lead to weakened bones and fractures.
Injection Site Reactions: Pain, swelling, or discoloration at the injection site is possible if extravasation occurs (iron leaks out of the vein).
Other common side effects: These include headache, dizziness, fatigue, nausea, and a metallic taste. A delayed flu-like reaction can sometimes occur, particularly with older iron dextran products.

Conclusion

If oral iron supplements are unsuitable, intravenous iron therapy provides an effective and rapid method to correct low iron levels. A range of modern IV injections exists, including ferric carboxymaltose, iron sucrose, and ferumoxytol, which offer different dosing schedules and administration times. While IV iron is generally safe, it carries risks of allergic reactions, hypotension, and, for some agents, hypophosphatemia. The choice of injection depends on the patient's specific condition and needs, and should always be determined by a healthcare provider. This approach ensures patients receive the most appropriate and effective treatment for their iron deficiency, especially in cases where oral therapy is not an option.

Further information on iron deficiency and IV iron can be found on the Cleveland Clinic website.

Disclaimer: This information is for general knowledge and should not be taken as medical advice. Consult with a healthcare professional before starting any new supplement regimen.

Frequently Asked Questions

It can take several days to a week after starting an intravenous iron treatment before you begin to feel better. A more complete increase in iron and hemoglobin levels can take up to two months.

The most common IV iron injections include ferric carboxymaltose (Injectafer), iron sucrose (Venofer), and ferumoxytol (Feraheme). Each is prescribed based on the patient's medical condition and needs.

You may be a candidate for IV iron if you have severe iron deficiency, cannot tolerate oral iron supplements, or have conditions like chronic kidney disease, inflammatory bowel disease, or have had bariatric surgery that affects iron absorption.

Common side effects include headache, dizziness, nausea, changes in taste, flushing, and temporary rises in blood pressure. Some patients might experience fatigue or muscle aches in the days following the infusion.

Yes, allergic reactions, including severe anaphylactic-type reactions, are possible, although rare with modern IV iron products. For this reason, patients are monitored for a period after receiving an infusion.

IV iron is considered effective and safe in the second and third trimesters of pregnancy when oral iron is not tolerated or is ineffective. Pregnant women with severe iron deficiency anemia are often treated with IV iron to quickly increase levels, with close monitoring.

The duration of an iron infusion depends on the specific product used. Newer, high-dose formulations like Injectafer and Feraheme can be infused in as little as 15 minutes, while others may take longer.