Injectafer (ferric carboxymaltose) is a prescription brand-name medication. It’s approved by the Food and Drug Administration (FDA) to treat iron deficiency anemia (IDA) in certain adults. Anemia is a condition in which you have low levels of red blood cells. When anemia causes a lack of iron in your body, it’s known as IDA.

Typically, Injectafer is used as a short-term treatment to bring your iron levels up to normal. But if your IDA comes back, you may be able to repeat the treatment.

Here are some fast facts on Injectafer:

  • Active ingredient: ferric carboxymaltose
  • Drug class: iron replacement product
  • Drug form: liquid given as either an intravenous (IV) infusion* or a slow IV injection*

Like other drugs, Injectafer can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Injectafer, including details on its full uses, see this article.

* With an IV infusion, you receive an injection into a vein, and the drug is dripped in from an IV bag over a period of time. With a slow IV injection, you receive a slow injection into a vein.

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.

These are just a few of the more common side effects reported by people who took Injectafer in clinical trials:

Mild side effects can occur with Injectafer use. They don’t differ depending on whether you receive the drug as an intravenous (IV) infusion or a slow IV injection.*

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 of Injectafer can include:

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 side effects of the medication. If you develop a side effect while taking Injectafer and want to tell the FDA about it, visit MedWatch.

* With an IV infusion, you receive an injection into a vein, and the drug is slowly dripped in from an IV bag over a period of time. With a slow IV injection, you receive a slow injection into a vein.
† For more information on this side effect, see the “Side effect specifics” section below.

Although not common, Injectafer may cause serious side effects. They don’t differ depending on whether you receive the drug as an intravenous (IV) infusion or a slow IV injection.*

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 taking 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† can include:

* With an IV infusion, you receive an injection into a vein, and the drug is slowly dripped in from an IV bag over a period of time. With a slow IV injection, you receive a slow injection into a vein.
† To learn more about the side effects in this list, see the “Side effect specifics” section below.

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

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 (low level of phosphorus in the blood).

And, very rarely, Injectafer may cause long-lasting skin darkening at the injection site.

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

Can Injectafer cause side effects that require additional treatment?

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

For example, Injectafer may cause:

  • Allergic reaction. This may be serious or even life threatening. In such cases, you may require emergency treatment.
  • Serious hypophosphatemia (a low level of phosphorus in the blood). It may be treated with either diet or medication.
  • Rises in blood pressure. They usually aren’t long-lasting but may require treatment to lower them.

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

Can Injectafer cause weight gain?

No, Injectafer itself shouldn’t cause you to gain weight.

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 lead you to lose weight 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.

High blood pressure

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

Rarely, Injectafer can cause severe high blood pressure, which can cause symptoms such as:

  • dizziness
  • flushing in your face (temporary warmth, redness, or deepening of skin color)
  • 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

You can be aware of symptoms of severe high blood pressure, which are mentioned above.

After each dose of Injectafer, your doctor or another healthcare professional 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 or healthcare professional right away. They can treat you as needed.

Severely low level of phosphorus

Treatment with Injectafer can cause the level of phosphorus in the blood to become low. This is called hypophosphatemia.

In most cases, this side effect occurred in people who received multiple treatments of Injectafer. Hypophosphatemia may also be more likely to happen in people who have an increased risk for the condition. This includes people who:

Most cases of low blood phosphorus from Injectafer treatment aren’t serious and won’t cause symptoms. It’s very rare that the drug causes severe hypophosphatemia.

What you can do

While you’re being treated with Injectafer, your doctor will monitor your blood phosphorus levels if you’re at risk for this side effect.

Be aware of symptoms of hypophosphatemia if you receive treatment with Injectafer. When mild, it may cause a general feeling of weakness. But most mild cases of hypophosphatemia don’t cause symptoms.

Severe hypophosphatemia can cause symptoms including:

  • changes in mental status
  • numbness
  • seizures
  • weakness

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, you may require more immediate treatment, such as phosphorus given intravenously (through a vein).

Skin darkening at the injection site

Although very rare, it’s possible to experience skin 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 given as an intravenous (IV) infusion* or IV injection leaks into the site around the injection. In some cases, the darkening from Injectafer may be long term.

What you can do

You really can’t do anything yourself to help prevent skin darkening at the injection site. But your doctor or another healthcare professional will monitor you for at least 30 minutes after your dose. If they notice any extravasation, they’ll immediately stop your IV infusion or slow IV injection†. For future doses of Injectafer, they’ll choose a different injection site.

* With an IV infusion, you receive an injection into a vein, and the drug is dripped in from an IV bag over a period of time.
† With a slow IV injection, you receive a slow injection into a vein.

Allergic reaction

As with most drugs, Injectafer can cause allergic reaction in some people. This side effect was rare in clinical studies of the drug.

Symptoms can be mild or serious and can include:

  • rash
  • itching
  • flushing (temporary warmth, redness, or deepening of skin color)
  • severe low blood pressure
  • loss of consciousness

After each Injectafer dose you receive, your doctor or another healthcare professional 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 taking Injectafer. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Injectafer. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include the following:

Low level of phosphorus. Treatment with Injectafer can cause hypophosphatemia, which is a low level of phosphorus in the blood. If you already have hypophosphatemia, the drug may make this condition worse. Before you receive Injectafer, talk with your doctor if you have hypophosphatemia. They can recommend a treatment plan that’s right for you.

High blood pressure. Injectafer treatment can cause short-term increases in blood pressure. If you already have high blood pressure, the drug could cause your blood pressure to rise to dangerous levels. Before you receive Injectafer, be sure to talk with your doctor if you have high blood pressure. They can recommend the right treatment plan for you.

Allergic reaction. You shouldn’t take Injectafer if you’ve ever had an allergic reaction to the drug or any of its ingredients. Talk with your doctor about other treatments that might be better choices for you.

Alcohol use with Injectafer

There isn’t a known interaction between Injectafer and drinking alcohol. But consuming large amounts of alcohol can cause anemia in some people. This is because alcohol can affect your body’s ability to absorb the nutrients it needs to make red blood cells.

For this reason, talk with your doctor about how much alcohol is safe for you to drink while using Injectafer.

Pregnancy and breastfeeding while using Injectafer

Below is some information on using Injectafer during pregnancy and while breastfeeding.

Pregnancy

It’s not known if it’s safe to be treated with Injectafer while pregnant. Studies haven’t shown any issues when the drug was given during pregnancy. But these studies weren’t specifically designed to determine if the drug was safe to use while pregnant.

Talk with your doctor about the safest treatment for your anemia if you’re pregnant or plan to become pregnant.

Breastfeeding

It isn’t known if it’s safe to be treated with Injectafer while breastfeeding. The iron released by the drug is present in human breast milk. But it isn’t known if this could cause side effects in a breastfed child.

If you choose to breastfeed while taking Injectafer, the manufacturer of the drug recommends monitoring your child for diarrhea or constipation.

Talk with your doctor about the safest treatment for your anemia if you’re breastfeeding or plan to breastfeed your child.

Treatment with Injectafer doesn’t commonly cause side effects. And when they do occur, they’re usually mild. Most mild side effects of the drug go away with time and don’t require medical attention.

Some of the most common side effects reported in people taking Injectafer in clinical trials include:

Although rare, Injectafer injections can cause serious side effects. You should talk with your doctor if you experience symptoms of:

You should also talk with your doctor if you become pregnant while being treated with Injectafer.

If you’d like to learn more about Injectafer, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Note: For more information on iron deficiency anemia, see this list of blood and hematology articles.

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.