As with other drugs, Injectafer (ferric carboxymaltose) can cause side effects, such as nausea, high blood pressure, and flushed skin. If the side effects of Injectafer become difficult to tolerate, talk with your doctor.

Injectafer is a brand-name medication prescribed for iron deficiency anemia (IDA) in certain adults and children ages 1 year and older. It’s given as an IV infusion or a slow IV injection.

The side effects of Injectafer may vary in adults and children.

If you have problems with side effects from Injectafer, talk with your doctor or pharmacist. They can discuss ways to manage side effects or other available treatment options.

Injectafer can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days or weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

More common side effects reported in adults receiving Injectafer include:

More common side effects reported in children receiving Injectafer include:

  • hypophosphatemia
  • injection site reactions
  • skin rash
  • headache
  • vomiting

Mild side effects can occur with Injectafer treatment. This list doesn’t include all possible mild side effects reported with the drug. To learn more, you can refer to Injectafer’s prescribing information.

Mild side effects reported in adults receiving Injectafer include:

  • nausea
  • high blood pressure
  • flushed skin
  • dizziness
  • injection site reaction, including skin discoloration
  • skin redness or other color changes
  • hypophosphatemia
  • vomiting
  • changes in sense of taste
  • constipation
  • headache
  • low blood pressure

Mild side effects reported in children receiving Injectafer include:

  • hypophosphatemia
  • injection site reactions
  • skin rash
  • headache
  • vomiting
  • the common cold
  • flushed skin

How long side effects of Injectafer last vary from person to person. These side effects may be temporary, lasting a few days or weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while receiving Injectafer and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

For more information about some of these side effects, see the “Side effect specifics” section.

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Injectafer may cause serious side effects. The list below may not include all possible reported serious side effects of the drug. For more information, you can refer to Injectafer’s prescribing information.

If you develop serious side effects while receiving Injectafer, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects reported in adults receiving Injectafer include:

Serious side effects reported in children receiving Injectafer include:

For more information about some of these side effects, see the “Side effect specifics” section.

Injectafer may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How do the side effects of Injectafer compare with Venofer?

Both Injectafer and Venofer (iron sucrose) are brand-name prescription injections used to treat IDA in people with chronic kidney disease. So they may have similar side effects.

Like Injectafer, Venofer can cause nausea, changes in taste, dizziness, and injection site reactions. Both drugs can also cause severe allergic reactions.

Injectafer and Venofer treatment can also cause different side effects. The side effects you may experience with either drug can also vary.

If you have questions about the side effects of Injectafer versus Venofer, talk with your doctor.

Does Injectafer have any long-term side effects?

Injectafer isn’t likely to cause any long-term side effects. However, some people may experience severe hypophosphatemia. Very rarely, Injectafer may also cause long-lasting skin discoloration at the injection site.

For more information on these two side effects, see the “Side effect specifics” section. You can also talk with your doctor.

Can Injectafer cause side effects that require additional treatment?

It’s possible to experience side effects from Injectafer that require additional treatment.

For example, Injectafer may cause:

  • allergic reaction, which may be serious or even life threatening, and may require emergency treatment
  • severe hypophosphatemia, which may be treated with either diet or medication
  • high blood pressure, which isn’t usually long lasting, but may require treatment to lower it

For more information on each of these potential side effects, see the “Side effect specifics” section.

Can Injectafer cause weight gain?

No, Injectafer itself doesn’t cause weight gain as a side effect. But you may have weight changes as your anemia improves. This is often due to anemia symptoms easing.

For example, if you have a lack of appetite, you may regain it once your anemia is treated. This could cause you to gain weight. Or if you have severe fatigue, you may regain your energy due to receiving anemia treatment. And this may cause weight loss because you’re more active.

If you have questions or concerns about managing your weight while using Injectafer, talk with your doctor. They can help develop a diet and exercise plan for you.

Learn more about some of the side effects that Injectafer may cause.

Skin discoloration at the injection site

Although very rare, it’s possible to experience skin discoloration, such as darkening at the site where an Injectafer injection is given. This may be due to a type of skin reaction called extravasation. With this reaction, a drug that’s given as an IV infusion or slow IV injection leaks into the site around the injection. In some cases, the discoloration from Injectafer may be long term.

What you can do

Your doctor or another healthcare professional will monitor you for at least 30 minutes after injecting your dose. If they notice any extravasation, they’ll immediately stop your IV infusion or injection. For future doses of Injectafer, they’ll choose a different injection site.

High blood pressure

Treatment with Injectafer can cause increases in blood pressure in some people. These increases aren’t usually serious. They generally don’t last more than 30 minutes and go away on their own without treatment.

In rare cases, Injectafer can cause severe high blood pressure, which can cause symptoms such as:

  • dizziness
  • flushed skin on the face
  • nausea
  • chest pain

Severe high blood pressure from Injectafer isn’t long lasting. However, it may require treatment for it to return to a normal level.

What you can do

After each dose of Injectafer, your doctor will monitor you for at least 30 minutes for high blood pressure. This includes severe high blood pressure. If you experience any of the above symptoms after an Injectafer injection, tell your doctor right away. They can treat the high blood pressure as needed.

Severely low level of phosphorus

Treatment with Injectafer can cause hypophosphatemia, which is a low level of phosphorus (a type of mineral) in the blood. This side effect often occurred in people who received multiple treatments of Injectafer in clinical trials.

Most cases of low blood phosphorus from Injectafer treatment aren’t serious and won’t usually cause symptoms. However, when mild, it may cause a general feeling of weakness.

It’s very rare that the drug causes severe hypophosphatemia, but symptoms may include:

  • changes in mental status
  • numbness
  • seizures
  • weakness

Hypophosphatemia may be more likely to happen in people who have an increased risk for the condition. This includes people who:

What you can do

If you have an increased risk of hypophosphatemia, your doctor will monitor your blood phosphorus levels during Injectafer treatment.

If you have symptoms of hypophosphatemia, talk with your doctor right away. For a mild case or no symptoms at all, your doctor may recommend medication or adding more phosphorus to your diet. But if you have severe hypophosphatemia, your doctor may recommend more immediate treatment, such as phosphorus given intravenously (through a vein).

Allergic reaction

As with most drugs, Injectafer can cause allergic reaction in some people. This side effect was rare in clinical trials of the drug, but it can be severe.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushed skin
  • severe low blood pressure
  • loss of consciousness

After each Injectafer dose you receive, your doctor will monitor you for at least 30 minutes for any symptoms of allergic reaction. They’ll have supplies and medications ready to treat any reaction you may have.

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep receiving Injectafer. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Before starting Injectafer treatment, discuss your health history with your doctor. Injectafer may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • previous treatment with Injectafer
  • trouble absorbing certain vitamins or phosphate in your body
  • low level of phosphorus
  • vitamin D deficiency
  • high blood pressure
  • inflammatory bowel disease
  • hyperparathyroidism
  • allergic reaction, including allergic reaction to iron given into your vein
  • alcohol consumption
  • pregnancy
  • breastfeeding

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.