If you have hives, asthma, or nasal polyps, your doctor may prescribe Xolair.

It’s a prescription drug used in certain situations for adults and some children with:

  • a certain type of hives
  • moderate to severe long-lasting asthma caused by allergens
  • nasal polyps, together with other medications

To learn more about hives and how to treat them with Xolair, see the “Is Xolair used for hives?” section below. To learn more about using Xolair for asthma and nasal polyps, see the “Is Xolair used for other conditions?” section below.

Note: You should not use Xolair for sudden trouble breathing or severe breathing problems that don’t improve with treatment. These are both possible symptoms of asthma. Instead, you should use a rescue inhaler for sudden breathing problems. To learn more, see “Receiving other drugs with Xolair” in the “How is Xolair administered?” section below.

Xolair basics

Xolair contains the drug omalizumab, which is a biologic medication. Biologics are made from parts of living organisms.

Xolair isn’t available in a biosimilar form. (Biosimilars are like generic drugs. But unlike generics, which are made for nonbiologic drugs, biosimilars are made for biologic drugs.) Instead, omalizumab is only available as the brand-name drug Xolair.

Xolair comes as a solution inside prefilled syringes and as a powder inside vials. (Your doctor will mix the powder with sterile water.)

You’ll take Xolair as an injection under your skin. Your doctor will give you your first few doses. If they recommend that it’s safe to do so, you may be able to give the drug to yourself after a while.

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

Like most drugs, Xolair may cause mild or serious side effects. The lists below describe some of the more common side effects. 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 Xolair. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a list of some of the mild side effects that Xolair can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Xolair’s medication guide.

Mild side effects of Xolair 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 about this side effect, see the “Side effect focus” section below.

Serious side effects

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

Serious side effects of Xolair that have been reported include:

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

Note: This combination of symptoms can happen between 1 and 5 days after your first dose of Xolair. But the symptoms can also happen after later injections of the drug. If you have this combination of symptoms or any one of them, talk with your doctor right away. Your doctor will tell you if you should continue receiving Xolair.

Side effect focus

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

Boxed warning

Xolair has a boxed warning for anaphylaxis. A boxed warning is a serious warning from the Food and Drug Administration (FDA). This warning is described below.

Anaphylaxis. Anaphylaxis is a life threatening allergic reaction. With anaphylaxis to Xolair, you may have:

Anaphylaxis can happen after you’ve received your first dose of Xolair. But some doctors have reported anaphylaxis in people who’d been taking Xolair for over a year.

What might help

Your doctor will give you your first few doses of Xolair. This way, they can closely monitor you for anaphylaxis.

If you have any symptoms of anaphylaxis, your doctor will manage your reaction. And they’ll have you stop treatment with Xolair.

Before starting Xolair, your doctor will talk with you about symptoms of anaphylaxis. If you notice any symptoms of anaphylaxis while you’re taking Xolair, you must go to a hospital right away.

If your doctor determines that your risk of anaphylaxis with Xolair is low, they may have you inject doses of the drug yourself. To decide this, your doctor will consider your risk factors for anaphylaxis.

Your doctor will give you at least your first three doses of Xolair. Then, they may have you inject doses yourself if you didn’t have any reaction to the first three doses. Your doctor will also assess whether you or a caregiver are able to recognize and treat anaphylaxis. And they’ll check to be sure you can inject Xolair using the proper technique.

Hair loss

You may notice hair loss when you’re taking Xolair. But it’s not known how often this occurs with the drug.

One study reported findings from three people who had hair loss with Xolair. Their hair loss happened after they received their first dose of the drug. The hair loss was temporary, only lasting up to 4 months.

What might help

Hair loss with Xolair isn’t a common side effect. And it may be temporary.

If you’re concerned about losing hair with Xolair, talk with your doctor. They can help you decide whether the benefits of Xolair outweigh its possible side effects.

Cancer

Some people have developed cancer while taking Xolair. The types of cancer that can occur with this drug include cancer of the:

It’s not known if people with a high risk of cancer have a higher risk with Xolair. This includes people who are older and those who smoke.

What might help

Before starting Xolair, tell your doctor if you’ve had or currently have cancer.

If you’re concerned about getting cancer while taking Xolair, talk with your doctor. They can help you decide if the risk of cancer outweighs the benefits of Xolair for treating your condition.

Also, check with your doctor about recommended screening options for cancer, given your age and medical history.

Allergic reaction

Some people may have an allergic reaction to Xolair. It’s possible to be allergic to the ingredients contained in the drug. Some people may also react to the latex found on the needle cap of Xolair prefilled syringes.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • 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.

It’s important to know that Xolair has a boxed warning for anaphylaxis, which is a life threatening allergic reaction. To learn more about this, see the section above called “Boxed warnings.”

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

If you have a certain type of hives, your doctor may recommend Xolair.

It’s a prescription drug used to treat hives due to chronic idiopathic urticaria (CIU). With CIU, you have hives or angioedema (inflammation in deep layers of your skin). And the condition lasts for 6 weeks or more.

Xolair is prescribed for adults and children ages 12 years and older. To take Xolair for hives, you must have already tried antihistamine treatments, such as cetirizine (Zyrtec) or loratadine (Claritin). And these treatments didn’t help with your condition.

Hives can be itchy and may appear as pink-to-red areas on your skin. Usually, the center of the area is pale in color. While hives can occur anywhere on the body, some areas are more prone to hives, such as:

  • waist
  • armpits
  • groin

Xolair isn’t used to treat hives that result from allergic reactions or other forms of hives. It’s only used for the type of hives described above.

In addition to treating hives, Xolair is used for other purposes. See the “Is Xolair used for other conditions?” section below.

If you have asthma or nasal polyps, your doctor may prescribe Xolair.

It’s a prescription drug used for:

  • Moderate to severe long-lasting asthma. For this condition, Xolair can be used in adults and children ages 6 years and older. Asthma is a long-lasting breathing disease. With asthma, you have inflammation in your airways, and your airways are narrower than usual. People with asthma have trouble breathing, coughing, and wheezing. Doctors prescribe Xolair for people whose asthma isn’t well managed with inhaled corticosteroids. Their asthma is caused by certain allergens, such as pollen.
  • Nasal polyps. For this condition, Xolair is used in adults. Nasal polyps are noncancerous growths that occur inside the nose. With nasal polyps, you might have long-lasting sinus infections. Nasal polyps can affect your quality of life because the symptoms, including a runny nose and face pain, are usually long-lasting. You might also have a reduced sense of smell. Doctors prescribe Xolair for people whose nasal polyps didn’t get better with corticosteroids given into the nose. And it’s used together with other treatments for this condition.

Note: You should not use Xolair for sudden trouble breathing or severe breathing problems that don’t improve with treatment. These are both possible symptoms of asthma. Instead, you should use a rescue inhaler for sudden breathing problems. To learn more, see “Receiving other drugs with Xolair” in the “How is Xolair administered?” section below.

In addition to treating these conditions, Xolair is used in some situations for hives. See the section just above called “Is Xolair used for hives?” to learn more.

Your doctor will recommend the dosage of Xolair that’s right for you. Below are commonly used dosages, but your doctor will determine the dosage you’ll receive.

Forms and strengths

Xolair comes in two forms:

  • a powder inside vials that your doctor will mix with sterile water
  • a solution inside prefilled syringes

Vials and syringes of Xolair can only be used once. The powder comes in one strength: 150 milligrams (mg). The solution comes in two strengths: 75 mg and 150 mg.

You’ll take Xolair as an injection under your skin. Your doctor will give you your first few doses. If they recommend that it’s safe to do so, you may be able inject the drug yourself after a while.

Recommended dosages

Here’s a dosage chart that shows Xolair’s typical doses based on the condition you’re treating.

You’ll take Xolair:
For hives:once every 4 weeks
For asthma:once every 2 or 4 weeks
For nasal polyps:once every 2 or 4 weeks

Your doctor will tell you how much Xolair you’ll need to inject for each dose.

Your dosage of Xolair will depend on your condition and your weight.

For some conditions, it also varies based on the level of certain antibodies in your blood. (Antibodies are immune system proteins.) So for these conditions, you’ll have a blood test to measure your antibody level before starting Xolair.

But for hives, you won’t need a blood test before starting Xolair. This is because the drug’s dosing for hives doesn’t depend on how many antibodies are in your blood.

Questions about Xolair’s dosage

Here’s a list of common questions related to doses of Xolair.

  • What if I miss a dose of Xolair? If you’re receiving Xolair doses from your doctor, call your doctor’s office and reschedule the appointment for your injection. Your doctor will tell you when your next dose should be given. If you’re injecting Xolair doses at home, call your doctor and ask them when you should take your next dose.
  • Will I need to use Xolair long term? You may need to use Xolair long term. The conditions that Xolair treats are long-lasting diseases. Talk with your doctor to find out how long you’ll need to take Xolair.
  • How long does Xolair take to work? Xolair takes several months to start working. How long it takes to work depends on the condition it’s treating. You might only notice a reduction in your symptoms after you’ve been taking Xolair for a while. Your doctor can tell you when you can expect to notice your symptoms lessen.
  • Should I take doses of Xolair with food? You don’t need to take Xolair doses with food. Xolair will be injected under your skin. Having a full or empty stomach won’t change how much medication your body absorbs.

Costs of prescription drugs can vary depending on many factors. These include what your insurance plan covers and which pharmacy you use. To find current prices for Xolair 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 Xolair manufacturer’s website to see if they have support options.

Your doctor will explain how Xolair will be given to you. They will also explain how much you’ll receive and how often the drug will be administered.

Receiving Xolair

You’ll take Xolair as an injection under your skin.

Your doctor will give you your first few Xolair shots. If they recommend that it’s safe to do so, you may be able to give the drug to yourself after a while.

Depending on your prescribed dose, your doctor may split it into two injections and give them in different sites. Splitting larger doses may help lower your risk of skin reactions with the injections.

Xolair injection sites

You or your doctor can inject Xolair into:

  • the front or middle of your thighs
  • your belly

But you must avoid injecting Xolair around the skin of your belly button.

Additionally, if your doctor or a caregiver is injecting Xolair for you, it can be given into the outer area of your upper arm.

Receiving Xolair with other drugs

Depending on the condition you have, you might need to take Xolair with other medications.

Xolair with other drugs for hives

To help with inflammation from hives, you may use corticosteroid creams with Xolair. These could include creams such as betamethasone valerate (Dermabet).

Xolair with other drugs for asthma

For asthma, you should not use Xolair for sudden trouble breathing or severe breathing problems that don’t improve with treatment. These are both possible symptoms of asthma. Instead, you should use a rescue inhaler for sudden breathing problems.

Examples of rescue inhalers include:

Additionally, for asthma, you can still use corticosteroid inhalers regularly. Examples of these drugs include:

Xolair with other drugs for nasal polyps

For nasal polyps, Xolair is always used together with corticosteroid nasal sprays, such as mometasone (Nasonex) and budesonide (Rhinocort).

Other medications you may take with Xolair if you have nasal polyps include antibiotics for sinus infections, such as:

  • amoxicillin-clavulanate (Clavulin)
  • doxycycline (Vibramycin)
Questions for your doctor

You may have questions about Xolair 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 Xolair 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.

Find the answers below to some commonly asked questions about Xolair.

How does Xolair work? Is it an immunosuppressant?

Based on how Xolair works, it’s thought that the drug isn’t an immunosuppressant.

Xolair is a biologic (a drug made from parts of living organisms). Certain biologics work by weakening the activity of your immune system. But Xolair works differently.

It attaches to a protein in your body called immunoglobulin E (IgE). This is a protein made by the immune system, and it recognizes foreign substances in your body. IgE receptors are found on different immune system cells in your body. They cause inflammation when they’re activated by IgE.

Xolair blocks this activation and stops inflammation that’s responsible for asthma and nasal polyps. It also lowers the levels of IgE protein in the body, which helps relieve hives. This is the drug’s mechanism of action.

Xolair affects a different part of your immune system than other biologics. Other biologics affect your immune system’s ability to respond and fight off infections. So these medications may increase your risk for infections, including serious ones such as tuberculosis (TB).

Certain infections can occur during Xolair treatment, making it seem like the drug weakens your immune system. But it’s important to keep in mind that people with asthma and nasal polyps, which Xolair treats, already have a higher risk for infection.

If you have questions about how Xolair works and how it could affect your immune system, talk with your doctor or pharmacist.

Will I have withdrawal symptoms when coming off of Xolair?

Doctors haven’t reported withdrawal symptoms in people stopping Xolair. But if you stop taking the drug, symptoms of the condition you were treating may come back.

Don’t stop taking Xolair without first talking with your doctor. They can tell you what symptoms may occur if you stop taking this drug.

Does Xolair treat allergies or eczema?

No, Xolair doesn’t treat allergies or eczema. These are limitations to the use of Xolair, which means they’re situations when the drug can’t be used.

If you’d like to know more about treatment options for allergies or eczema, ask your doctor. They can recommend the best option for you.

To learn more about Xolair’s uses, see the “Is Xolair used for hives?” and “Is Xolair used for other conditions?” sections above.

Can Xolair cause weight gain or weight loss?

No, Xolair doesn’t affect body weight.

If you’re concerned about changes in your weight while you’re taking Xolair, talk with your doctor. They can recommend ways to help you maintain a moderate weight. This may include trying nutritional diets and exercises that are safe for you.

Is Xolair safe to take?

Your doctor will tell you if Xolair is safe for you to take.

In studies, the drug was considered safe for people taking it. Xolair does have some possible serious side effects. But your doctor will recommend if it’s safe for you, given your overall health.

Can I get a flu shot while taking Xolair?

Xolair doesn’t interact with vaccines, including the flu shot. In fact, people are encouraged to get vaccinated every year against influenza (the flu) if they’re taking Xolair.

One side effect of Xolair is lung infections. Getting vaccinated against the flu may help decrease your risk of getting sick with a lung infection.

Also, people taking Xolair for asthma should receive their yearly flu vaccine to help maintain the health of their lungs.

If you’d like to know more about getting a flu vaccine, talk with your doctor or pharmacist.

Some important things to discuss with your doctor when considering Xolair to treat your condition include:

  • your overall health
  • any other medical conditions you may have

Also, tell your doctor if you’re taking any other medications. This is because some drugs can interact with Xolair.

These and other considerations to discuss with your doctor are described below.

Interactions

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

Before taking Xolair, 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 Xolair.

Interactions with drugs or supplements

So far, there aren’t any known interactions between Xolair and other medications. Doctors haven’t reported that any vitamins, herbs, or supplements interact with Xolair.

But to be safe, before taking any medication, vitamin, herb, or supplement, talk with your doctor or pharmacist. They can tell you about any possible interactions that may occur with Xolair.

Other interactions

Although Xolair isn’t known to interact with other medications, herbs, or supplements, it may affect the results of a certain blood test.

After you receive Xolair, your levels of an immune system protein called immunoglobulin E (IgE) will increase. This increased IgE level can stay for up to 1 year after you’ve stopped taking Xolair.

To learn more about this, talk with your doctor.

Boxed warning

Xolair has a boxed warning for anaphylaxis. This is a serious warning from the Food and Drug Administration (FDA) about drug effects that may be dangerous.

Anaphylaxis is a life threatening allergic reaction. With anaphylaxis to Xolair, some people may have:

Anaphylaxis can happen after you receive your first dose of Xolair. But some doctors have reported anaphylaxis in people who’d been taking Xolair for over a year.

For more information about this side effect, see the “What are Xolair’s side effects?” section above.

Other warnings

Xolair 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 Xolair. Factors to consider include those in the list below.

  • Allergic reaction. If you’ve had an allergic reaction to Xolair or any of its ingredients, you should not take it. Ask your doctor what other medications are better options for you.
  • Parasite infections. If you live in an area with a high risk of parasite infections, Xolair may not be right for you. Xolair can increase your risk of a parasitic infection in your belly. Your doctor will check you for parasitic infections if you live in an area with a high risk of exposure to parasites. These include roundworm, hookworm, whipworm, and threadworm.
  • Reducing steroid dose. If you’re taking Xolair, don’t quickly stop steroids taken by mouth or inhalation. Your doctor will recommend if you need to stop taking steroids. If you need to stop these drugs, you must gradually reduce your dose. Your doctor will check you for steroid withdrawal symptoms while you stop steroid therapy. If you notice any symptoms, call your doctor right away. Withdrawal symptoms may include:
    • nausea or vomiting
    • diarrhea
    • belly pain
    • muscle or joint pain
    • changes in your mood
    • changes in your weight
    • headache
    • weakness

Xolair and alcohol

Some medications interact with alcohol. But Xolair isn’t one of them.

So far, there aren’t any reported interactions between alcohol and Xolair. But before starting Xolair, ask your doctor or pharmacist if it’s safe for you to drink alcohol. You may also need to tell your doctor how much alcohol you drink.

Alcohol can make some medical conditions worse. For instance, some people with nasal polyps feel worse after drinking. Keep in mind that Xolair is used to treat nasal polyps.

Depending on how much alcohol you drink, it may also reduce your immune system’s ability to fight off infections. This can increase your risk of getting infections, which Xolair may also do.

Additionally, alcohol can worsen and also cause some of the side effects of Xolair. These include dizziness, nausea, and fatigue.

Pregnancy and breastfeeding

Xolair doesn’t seem to affect pregnancy.

Experts reported that babies born to people who took Xolair during pregnancy had a low birth weight. But it’s not known whether this was caused by Xolair or the condition it was treating.

For instance, pregnancy complications can occur if someone’s asthma isn’t well managed. Keep in mind that Xolair is used for asthma in certain situations. Having asthma that’s not well managed can cause:

If you’re pregnant or considering pregnancy, tell your doctor before starting Xolair. Your doctor will help you manage your condition during pregnancy. They’ll tell you if the benefits of Xolair outweigh its possible risks.

It’s unknown whether Xolair is found in breast milk or if it affects how your body makes milk. In studies, experts didn’t see an increase in infections in breastfed children. (Infections are a possible side effect of this drug.)

If you’re breastfeeding or considering doing so while taking Xolair, talk with your doctor. They’ll help you decide if the benefits of Xolair outweigh its possible risks.

You may wonder how Xolair compares with some alternative drugs such as Dupixent.

Examples of similar drugs include:

Read on to learn more about some of these drugs. And be sure to ask your doctor which medication is right for you.

Xolair vs. Dupixent

Dupixent contains the active drug dupilumab, while Xolair contains the active drug omalizumab.

Both Xolair and Dupixent are used in certain situations for asthma in adults and some children. Dupixent is also used to treat other conditions, including eczema in adults and some children and long-lasting sinus infections in adults. And Xolair is used for nasal polyps and hives in some people.

Unlike Xolair, Dupixent doesn’t have a boxed warning. Boxed warnings are serious warnings from the Food and Drug Administration (FDA) about drug effects that may be dangerous.

To see a side-by-side breakdown of Xolair and Dupixent, check out this article.

Xolair vs. Nucala

Nucala contains the active drug mepolizumab, but Xolair contains the active drug omalizumab.

Both Xolair and Nucala are used in certain situations to treat asthma. In addition, Nucala treats sinus infections in people with nasal polyps. It’s also used for eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome. These are conditions in which you have a high level of eosinophils (a type of immune cell). Xolair is also used for nasal polyps and hives in some people.

Nucala also doesn’t have a boxed warning for anaphylaxis. Boxed warnings are serious warnings from the Food and Drug Administration (FDA) about drug effects that may be dangerous.

Here’s a detailed comparison of Xolair and Nucala.

Xolair vs. Fasenra

Fasenra contains the drug benralizumab, while Xolair contains the active drug omalizumab.

Like Xolair, Fasenra is used to treat asthma in adults and some children. But unlike Xolair, Fasenra isn’t used for hives or nasal polyps.

Xolair has a boxed warning for anaphylaxis. (Boxed warnings are serious warnings from the Food and Drug Administration [FDA] about drug effects that may be dangerous.) While anaphylaxis is a possible side effect of Fasenra, it’s not a boxed warning for Fasenra.

See this article to find out how Xolair compares with Fasenra.

If you have hives, asthma, or nasal polyps, your doctor may prescribe Xolair. To learn about how this drug is used, see the “Is Xolair used for hives?” and “Is Xolair used for other conditions?” sections above.

If you have questions about taking this drug, talk with your doctor or pharmacist. They can tell you about other treatments you can use for your condition.

Here’s a list of articles that you might find helpful:

Some questions to ask your doctor about Xolair may include:

  • Is Xolair a steroid injection?
  • Can I switch from receiving Xolair once every 2 weeks to once every 4 weeks?
  • What should I do if I accidentally inject more Xolair than my doctor prescribed?
  • What will happen if I don’t split my Xolair dose between different injection sites?

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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 another 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.