Firazyr (icatibant acetate) is a brand-name drug that’s prescribed for hereditary angioedema (HAE) in adults. Firazyr comes as a subcutaneous injection that’s used when needed to treat an HAE attack.

Firazyr is approved by the Food and Drug Administration (FDA) to treat hereditary angioedema (HAE) attacks in adults. It’s not used to prevent attacks. With HAE, you may experience swelling in your face, upper airway, buttocks, genitals, or hands and feet.

Firazyr belongs to a drug class called immunomodulators. Firazyr is available in a generic version.

Keep reading for specific information about the dosage of Firazyr, including its strength and how to use the medication. For a comprehensive look at Firazyr, see this article.

Note: This article describes typical dosages for Firazyr provided by the drug’s manufacturer. When using Firazyr, always follow the dosage prescribed by your doctor.

Below is information about Firazyr’s form, strength, and dosage.

Firazyr form

Firazyr comes as a liquid solution in a single-dose prefilled syringe. It’s given as a subcutaneous injection.

Firazyr strength

Firazyr comes in one strength of 30 milligrams per 3 milliliters (mg/mL).

Typical dosages

The following information describes dosages that are commonly used or recommended in adults. However, be sure to use the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for HAE

Doctors may prescribe Firazyr to treat HAE.

If your doctor prescribes Firazyr to you, your dose will likely be 30 mg. You’ll use this dose if you have an HAE attack. If your symptoms do not go away or if they return, you may use a second 30 mg dose 6 hours after the first dose.

You can use up to three 30-mg doses per day. This is the maximum dosage of Firazyr that’s recommended.

For more information about your specific dosage, talk with your doctor.

Long-term treatment

Firazyr is prescribed to treat HAE attacks. It doesn’t work to prevent attacks. For this reason, you’ll only use it to treat an HAE attack.

Talk with your doctor if you have questions about how long you can expect to take Firazyr.

Firazyr comes as a liquid solution in a single-dose prefilled syringe. It’s given as a subcutaneous injection.

With a subcutaneous injection, you’ll inject the medication under your skin. You’ll use the single-dose prefilled syringe to give yourself Firazyr. Your doctor will give you your first dose. Then, they’ll show you and/or your caregiver how to administer the drug. Make sure to inject Firazyr according to your prescribed instructions.

You can inject Firazyr into your abdomen. However, be sure not to inject Firazyr within 2 inches of your belly button.

It’s best to choose a different area of your abdomen each time you inject Firazyr. You should avoid areas where your skin is tender, hard, or irritated. This will reduce your risk of injection site reactions, such as bleeding or pain.

If you have questions about how to use Firazyr, talk with your doctor or pharmacist. There’s also a helpful video on the manufacturer’s website.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

It’s important that you do not use more Firazyr than your doctor prescribes. For some medications, using more than the recommended amount may lead to harmful effects or overdose.

Effects of an overdose

Overdose effects of Firazyr can include:

  • itching
  • skin discoloration
  • low blood pressure
  • injection site reactions
  • dizziness
  • fever

If you use more than the recommended amount of Firazyr

Call your doctor right away if you believe you’ve used too much Firazyr.

Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

Below are some frequently asked questions about Firazyr.

Is the dosage of Firazyr similar to the dosage of Kalbitor?

Yes, the forms and how often you take each drug are similar. Firazyr and Kalbitor are both subcutaneous injections used as needed to treat HAE.

The dose in milligrams for each drug differs because they have different active ingredients. (Kalbitor contains the active ingredient ecallantide.) 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 as soon as you inject it. It may take up to 2 hours to notice a decrease in your HAE symptoms. Your doctor will also monitor you during treatment to check whether the drug is working to treat your condition.

Talk with your doctor if you have questions about what to expect with Firazyr treatment.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Firazyr for you, they will prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes.

As with any drug, never change your dosage of Firazyr without your doctor’s recommendation. If you have questions about the dosage of Firazyr that’s best for you, talk with your doctor.

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 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.