If you have iron deficiency anemia (IDA), your doctor may prescribe Injectafer. With IDA, you have a low level of red blood cells that’s caused by not having enough iron.

Injectafer is a prescription drug that’s used in adults with IDA who either:

To learn more about IDA and how Injectafer is used for it, see the “What is Injectafer used for?” section below.

Injectafer basics

Injectafer contains the active drug ferric carboxymaltose, which is an iron replacement product. It comes as a solution that your doctor will inject into your vein.

Your doctor may administer Injectafer as either:

  • an iron infusion, which is an injection into your vein that lasts at least 15 minutes
  • a slow intravenous push, which is an injection into your vein that lasts 5 minutes or less

Injectafer isn’t available in a generic form. Instead, it’s only available in the brand-name form.

Read on to learn more about Injectafer’s side effects, uses, and more.

Like most drugs, Injectafer may cause mild or serious side effects. The lists below describe some of the more common side effects that Injectafer may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you may be taking

Your doctor or pharmacist can tell you more about the potential side effects of Injectafer. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a short list of some of the mild side effects that Injectafer can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Injectafer’s prescribing information.

Mild side effects of Injectafer that have been reported include:

Mild side effects of many drugs may go away within a few days or a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* For more information on this side effect, see the “Side effect focus” section below.

Serious side effects

Serious side effects from Injectafer can occur, but they aren’t common. If you have serious side effects from Injectafer, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects* of Injectafer that have been reported include:

* For more information on these side effects, see the “Side effect focus” section below.

Side effect focus

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

Low phosphorus levels

Injectafer may lower the level of phosphorus in your blood. This condition is also called hypophosphatemia.

Your risk for this side effect may be increased if:

  • you’re already at risk for low phosphorus levels, or
  • you require more than one dose of treatment with Injectafer

Risk factors for having a low phosphorus level include:

Most people won’t have any symptoms of low phosphorus level. But if you’re already at risk for having a low phosphorus level, you may develop symptoms. These symptoms can include fatigue (lack of energy), muscle weakness, loss of appetite, and bone pain or fractures.

Although rare, if your phosphorus level drops too low, you may develop complications. These can include:

  • rhabdomyolysis (a type of muscle tissue death)
  • trouble breathing
  • a type of anemia (low red blood cell level) that’s caused by your red blood cells dying more quickly than usual
  • irregular heartbeat

What might help

If you need to take Injectafer and you’re at risk for hypophosphatemia, your doctor will check your phosphorus levels. They’ll recommend whether it’s safe for you to receive this drug.

If you have any symptoms of low phosphorus level, tell your doctor right away. But if your symptoms feel life threatening, call 911 or your local emergency number.

Infusion-related or injection-related side effects

When you’re receiving Injectafer, you might develop injection site reactions where the drug is injected or infused into your body.

Infusion-related or injection-related side effects are skin reactions that include:

  • changes in the color of your skin where the drug is injected
  • fluid leaking from the injection site
  • pain at the injection site

Changes in skin color may last several months after a drug infusion. And sometimes, they can cause cosmetic concerns.

What might help

Your doctor can help prevent or reduce the risk of skin discoloration with Injectafer injections.

To help prevent this side effect, they can rinse the infusion tubing with a salt solution before removing the needle from your skin. This will stop Injectafer from leaking into the tissues under your skin around the injection site.

If you have concerns about side effects related to Injectafer infusions or injections, talk with your doctor.

Diarrhea

Diarrhea isn’t a common side effect of Injectafer. Compared to other forms of iron that are given by injection, the rates of diarrhea are similar with Injectafer.

Diarrhea may occur more often with iron replacement products that you take by mouth than it does with Injectafer.

What might help

If you get diarrhea with Injectafer, talk with your doctor. They may recommend over-the-counter medications to help relieve diarrhea. But be sure to talk with your doctor before taking any drugs to stop diarrhea.

If you have long-lasting kidney disease, you must avoid dehydration (low fluid level), which can happen with diarrhea. This is because dehydration can be very serious for people with kidney problems.

Rehydration is the first step to managing diarrhea. To replace your fluid and electrolyte losses from diarrhea, you may need to drink a rehydration solution. These rehydration solutions contain a mixture of salt, sugar, and water.

You can also manage diarrhea by eating foods such as bananas, rice, applesauce, and toast. It’s also helpful to avoid certain foods, such as dairy products, if you have diarrhea.

Allergic reaction

Some people may have an allergic reaction to Injectafer.

Symptoms of a mild allergic reaction can include:

  • rash
  • hives
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing or wheezing.

If you’re having an allergic reaction to Injectafer, you may also have very low blood pressure.

With a severe allergy to Injectafer, you may experience:

Call your doctor right away if you have an allergic reaction to Injectafer. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Your doctor will monitor you for at least 30 minutes after giving Injectafer to you. Most allergic reactions occur within minutes to a few hours after receiving this drug.

Rarely, medications can cause delayed allergic reactions. With a delayed allergic reaction, your body reacts to a drug after you’ve received it in the past without having a reaction.

For example, you can develop an allergic reaction with a second dose of Injectafer.

Delayed allergic reaction was reported after a second dose of ferric carboxymaltose given to a person. (Ferric carboxymaltose is the active drug in Injectafer.) In this case, the person received two different brand-name medications of ferric carboxymaltose.

Injectafer and Venofer are both iron replacement products that you’ll receive as an injection into your vein. Both of these medications are used to treat iron deficiency anemia (IDA). (With IDA, you have a low level of red blood cells that’s caused by not having enough iron.)

To see a side-by-side comparison of these drugs, view this drug article. And be sure to talk with your doctor about which medication is right for you.

Your doctor will explain how Injectafer will be administered to you. They’ll also explain how much you’ll be given and how often. Be sure to follow your doctor’s instructions. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Receiving Injectafer

Injectafer comes as a solution inside single-use vials. Your doctor will inject the drug into your vein.

Your doctor may administer Injectafer as either:

  • an iron infusion, which is an injection into your vein that lasts at least 15 minutes
  • a slow intravenous push, which is an injection into your vein that lasts 5 minutes or less

Infusion times for Injectafer may vary. Talk with your doctor about how long your infusions may last.

Dosage

Your dose of Injectafer depends on your body weight. The drug’s dosing guidelines suggest receiving two doses of Injectafer that are separated by at least 7 days.

How often Injectafer is given depends on whether your anemia (low red blood cell level) occurs again. Talk with your doctor about how many doses of the drug you’ll need.

There isn’t a pediatric dosing guideline for Injectafer because it’s not approved for use in children.

Questions about receiving Injectafer

Here are answers to some common questions about receiving Injectafer.

  • What if I miss a dose of Injectafer? You’ll receive Injectafer from your doctor. If you miss an appointment to receive Injectafer, call your doctor’s office to reschedule.
  • Will I need to use Injectafer long term? No, you won’t need to use Injectafer long term. Your doctor will give you two doses of Injectafer that are at least 7 days apart. Some people may need repeat doses if their anemia comes back. Talk with your doctor about how many doses of the drug you’ll need.
  • Should I take Injectafer with food? You’ll receive Injectafer by injection into your vein. How much of the drug your body absorbs doesn’t depend on whether you have an empty or a full stomach. But, for iron deficiency anemia, which Injectafer is used to treat, your doctor may recommend increasing iron in your diet. This could include eating iron-rich foods such as:
    • red meat or dark poultry meat
  • How long does Injectafer take to work? Injectafer starts to work quickly after your doctor injects the drug into your vein. After about 15 minutes, your red blood cells start to pull the iron from Injectafer into your blood.
Questions for your doctor

You may have questions about Injectafer and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions such as:
    • How will Injectafer affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So, don’t be afraid to ask questions or offer feedback on your treatment.

Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use. To find current prices for Injectafer in your area, visit WellRx.com.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. You can also visit the Injectafer manufacturer’s website to see if they have support options.

Injectafer and Feraheme are both iron replacement products that are used for iron deficiency anemia (IDA). (With IDA, you have a low level of red blood cells that’s caused by not having enough iron.)

These medications are each given as an injection into your vein. But they contain different active drugs.

For a detailed look at how these medications compare with each other, check out this drug article. And talk with your doctor to learn more.

Find answers to some commonly asked questions about Injectafer.

How long does Injectafer stay in your system?

Injectafer stays in your system between 28 and 60 hours. But your red blood cells may start pulling iron from Injectafer out of your blood stream 15 minutes after a dose is given.

How long do Injectafer’s side effects last? And are there any long-term side effects of the drug?

Most side effects of Injectafer last for only a short time.

For example, your blood pressure may temporarily rise after getting a dose of the drug. But it typically goes back down to your usual blood pressure level after 30 minutes.

On the other hand, some of Injectafer’s side effects may last several months. This includes skin discoloration where the drug is injected into your vein. Additionally, if your phosphorus level drops with Injectafer, it may take about 3 months to reach a normal level again.

For more information about these side effects of Injectafer, see the “What are Injectafer’s side effects?” section above. And talk with your doctor about what you can expect with this drug.

Does Injectafer cause weight gain?

No, Injectafer doesn’t cause weight gain.

If you’re concerned about weight gain, talk with your doctor. They can recommend ways to help you manage a body weight that’s healthy for you.

How does Injectafer work?

Injectafer works to treat iron deficiency anemia (IDA) by increasing levels of iron in your blood. (With IDA, you have a low level of red blood cells that’s caused by not having enough iron.)

With low levels of iron, your body can’t make enough hemoglobin. Hemoglobin is a protein in your red blood cells that carries oxygen to all your body’s cells.

After Injectafer is injected into your blood stream, it releases iron. Your red blood cells take up the iron and make hemoglobin.

Some important things to discuss with your doctor when considering treatment with Injectafer include:

  • your overall health
  • any medical conditions you may have

Tell your doctor if you’re taking medications. This is important to do because some medications can interfere with Injectafer. These and other considerations to discuss with your doctor are described below.

Interactions

Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

Before receiving Injectafer, be sure to tell your doctor about all medications you take (including prescription and over-the-counter types). Also describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Injectafer.

Interactions with drugs or supplements

There aren’t any known interactions between Injectafer and any vitamins, herbs, or supplements. But before starting Injectafer, talk with your doctor or pharmacist about any other medications and vitamins you’re taking.

Other interactions

Injectafer may interact with certain lab tests.

Specifically, within 24 hours after receiving Injectafer, blood tests may overestimate how much iron you have in your blood. This happens because the blood tests can’t tell the difference between the iron in your blood and the iron from Injectafer that was just given to you.

Be sure to tell your doctor you’re taking Injectafer before you have any blood tests done.

Warnings

Injectafer may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Injectafer. Factors to consider include those in the list below.

  • Low phosphorus level (hypophosphatemia). If you’re at risk for having a low phosphorus level, Injectafer may lower your phosphorus levels. Your doctor will monitor your phosphorus levels and correct any deficiencies. It may take up to 3 months to reach normal levels of phosphorus.
  • Allergic reaction. If you’ve had an allergic reaction to Injectafer or any of its ingredients, you shouldn’t take Injectafer. Ask your doctor what other medications are better options for you. Also, it’s possible to have a delayed allergic reaction to Injectafer. This can happen even if you’ve gotten a dose of Injectafer in the past without having an allergic reaction. Your doctor will monitor you when you receive both your first and second doses of Injectafer. Also, your doctor will make sure that appropriate healthcare staff and equipment are available when you receive Injectafer. This is needed in case you have any symptoms of a severe allergic reaction.
  • High blood pressure. Your blood pressure may increase while you’re receiving doses of Injectafer. And this increase lasts for about 30 minutes. Some people may have facial flushing, dizziness, or nausea with the high blood pressure. Your doctor will monitor your blood pressure closely while you’re receiving Injectafer.

Use with alcohol

Some medications interact with alcohol, but Injectafer isn’t one of them.

But drinking alcohol may cause problems with your blood cells, including anemia (low red blood cell level).

Talk with your doctor about how much alcohol is safe for you to consume if you have anemia, including iron deficiency anemia (IDA), which Injectafer is used to treat. (With IDA, you have a low level of red blood cells that’s caused by not having enough iron.)

Pregnancy and breastfeeding

If you’re pregnant or breastfeeding, talk with your doctor before using Injectafer.

Use during pregnancy

The safety of Injectafer use during pregnancy has been studied. These studies didn’t show a link between Injectafer use and pregnancy-related issues.

But having untreated iron deficiency anemia (IDA), which Injectafer is used to treat, is risky during pregnancy. (With IDA, you have a low level of red blood cells that’s caused by not having enough iron.)

If IDA isn’t treated during pregnancy, people may have anemia after giving birth. Untreated IDA can also cause early delivery and low birth weight in babies.

But if Injectafer causes a severe reaction when used during pregnancy, you might experience severe low blood pressure. This can cause the developing fetus to have a low heart rate.

If you’re pregnant or planning to become pregnant, talk with your doctor before you take Injectafer. Your doctor will help you weigh the risks and benefits of IDA treatments, including Injectafer, while you’re pregnant.

Use while breastfeeding

Iron from Injectafer does pass into breast milk. But it’s not known how much of this iron is received by a child who is breastfed.

Because some iron passes through breast milk, doctors will monitor children who are breastfed for any changes in bowel movements, such as constipation or diarrhea. These changes may be side effects of iron treatment, such as Injectafer.

Your doctor will help you weigh the risks and benefits of breastfeeding while taking Injectafer.

If you have iron deficiency anemia (IDA), your doctor may prescribe Injectafer.

With anemia, you have a low level of red blood cells. And with IDA, you have a low level of red blood cells that’s caused by not having enough iron.

Injectafer is a prescription drug that’s used in adults with IDA who either:

Injectafer supplements extra iron for people who have anemia due to low iron levels. It contains the active drug ferric carboxymaltose. Carboxymaltose is a substance that attaches to iron. Once inside your body, it releases the iron, which your body uses to help reverse your anemia.

If you have questions about receiving Injectafer, talk with your doctor. They can tell you about other treatments you can use for your condition.

Some questions to ask your doctor about Injectafer may include:

  • Does Injectafer cure iron deficiency anemia?
  • What causes iron deficiency anemia?
  • What foods can I eat along with receiving Injectafer to improve my iron levels?
  • Do I have to take vitamin C along with Injectafer?

Disclaimer: Healthline 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.