Firazyr (icatibant) is a prescription drug that’s used to treat severe, sudden symptoms of hereditary angioedema (HAE). The drug comes as a liquid solution that’s injected under the skin as a one-time dose.

Firazyr is used in adults to treat immediate (severe and sudden) symptoms of HAE. This rare inherited condition causes severe swelling, commonly in the face, genitals, hands, and feet. It can also cause severe swelling of other body areas and can be life threatening.

The active ingredient in Firazyr is icatibant. (An active ingredient is what makes a drug work.) Firazyr belongs to a group of drugs called bradykinin B2 receptor antagonists.

This article describes the dosage of Firazyr, as well as its strength and how it’s given. To learn more about Firazyr, see this in-depth article.

This section describes the usual dosage of Firazyr. Keep reading to learn more.

What is Firazyr’s form?

Firazyr is available as a liquid solution for injecting under your skin.

What strength does Firazyr come in?

Firazyr comes in one strength of 10 milligrams (mg) per milliliter (mL).

What are the usual dosages of Firazyr?

Your doctor will prescribe the recommended dosage of Firazyr that provides the desired effect.

The information below describes the dosage that is commonly used or recommended. Your doctor will determine the best dosage to fit your needs.

Dosage for HAE

The typical Firazyr dosage for adults with severe, sudden HAE symptoms is given at the first sign of symptoms. The dosage is 30 mg as a one-time dose.

Your doctor may give your dose of Firazyr. Or they may train you on how to recognize HAE symptoms and give the dose yourself. If your doctor gives you Firazyr, they’ll monitor you to check whether the drug is working for your condition.

Sometimes a one-time dose of 30 mg doesn’t provide relief or your HAE symptoms return. In this case, your doctor may prescribe an additional dose of 30 mg. But the additional dose cannot be given until 6 hours or more after your first dose.

You should not have more than three doses of Firazyr in a 24-hour period.

Firazyr is only for use as needed to treat severe, sudden symptoms of HAE.

Is Firazyr used long term?

Firazyr is usually used as a long-term treatment to manage severe, sudden symptoms of HAE. You and your doctor can discuss whether it’s safe and effective for your condition. If you both agree that it is, you’ll likely use it long term for treating these HAE symptoms.

Firazyr is not for regular use. It’s only for use as needed to treat severe, sudden symptoms of HAE.

If you have questions about how long you’re likely to use Firazyr, talk with your doctor.

The dosage of Firazyr your doctor prescribes may depend on several factors. These include:

  • the severity of the condition the drug is treating
  • other medications you may be taking

Firazyr is available as a liquid solution that’s given as an injection under your skin. Your doctor or another healthcare professional may give you doses of Firazyr. They will inject Firazyr into your belly area.

If your doctor gives you Firazyr, they’ll monitor you to check whether the drug is working for your condition.

In some cases, your doctor may show you how to give Firazyr injections at home. If so, they or your pharmacist will provide instructions on how to give the doses. The prescribing information also has step-by-step instructions on how to give a dose of the medication.

For information on the expiration, storage, and disposal of Firazyr, talk with your doctor or pharmacist.

Accessible drug containers and labels

Some pharmacies provide medication labels that:

  • have large print
  • use braille
  • feature a code you can scan with a smartphone to change the text to audio

Your doctor or pharmacist may be able to recommend pharmacies that offer these accessibility features if your current pharmacy doesn’t.

Firazyr is used only to treat severe, sudden symptoms of HAE. It is not for regular use.

Your doctor may give you doses of Firazyr, or they may teach you how to give doses yourself at home. They’ll discuss signs of HAE to watch for, your dose of Firazyr, and when to give a dose.

Do not give more Firazyr than your doctor prescribes, as this can lead to harmful effects.

What to do in case you give too much Firazyr

Call your doctor right away if you think you’ve given too much Firazyr. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have new symptoms or worsening HAE symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

Below are answers to some commonly asked questions about Firazyr’s dosage.

Is Firazyr’s dosage similar to the dosages of Kalbitor or Cinryze?

No, not exactly. Firazyr (icatibant), Kalbitor (ecallantide), and Cinryze (C1 esterase inhibitor [human]) all help treat or prevent HAE symptoms. But their doses and strengths differ.

Firazyr and Kalbitor are used to treat sudden, severe symptoms of HAE. But Cinryze is used to help prevent HAE symptoms.

Firazyr is approved for use only in adults. It comes as a liquid solution for injection under your skin. A healthcare professional may give the doses or train you how to give them at home. Your dose depends on how your body responds to treatment.

Kalbitor is approved for use in adults and children ages 12 years and older. A healthcare professional gives it by injection under the skin. Your dose depends on how your body responds to treatment.

Cinryze is approved for adults and children ages 6 years and older. It comes as a powder that’s mixed into a solution for injecting by intravenous (IV) infusion into a vein. A doctor may give you doses or train you to give doses yourself. Your dosage depends on your age and how your body responds to treatment. You may receive doses every 3–4 days.

The dose in milligrams for each drug differs.

Your doctor will prescribe the drug and the dosage that’s right for you. To learn more about how these drugs compare, talk with your doctor.

How long does it take for Firazyr to start working?

Firazyr starts to work after your first dose. In studies, researchers measured how much the HAE symptoms of people taking Firazyr were reduced.

They measured this using a visual analog score (VAS) that checks skin swelling, abdominal (belly) pain, and skin pain. The VAS in a majority of people in these studies was reduced by 50% within about 2 hours of a dose.

If your doctor gives you a dose of Firazyr, they’ll monitor you to check whether the drug is working to treat your condition.

After a dose, sometimes symptoms don’t lessen or they return. In this case, your doctor may recommend giving another dose of Firazyr 6 hours or more after the first dose. You should not have more than three doses of Firazyr in a 24-hour period.

If you have other questions about what to expect from your Firazyr treatment, talk with your doctor.

The sections above describe the usual dosage provided by Firazyr’s drugmaker. If your doctor recommends this drug, they’ll prescribe the dosage that’s right for you.

Talk with your doctor if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask your doctor:

  • If my symptoms return after 24 hours of giving a Firazyr dose, can I give myself another dose?
  • Will my risk of side effects increase if I need two doses of Firazyr in a 24-hour period?
  • How does the dosage of Firazyr compare with the dosage of Takhzyro (lanadelumab-flyo)?

To learn more about Firazyr, see this article.

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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.