Haegarda (C1 esterase inhibitor subcutaneous [human]) is a brand-name drug that’s prescribed to prevent hereditary angioedema attacks in adults and some children. Haegarda comes as a subcutaneous injection that’s typically used twice per week.

Haegarda is approved by the Food and Drug Administration (FDA) to prevent hereditary angioedema (HAE) attacks in adults and children ages 6 years and older. With HAE, you get sudden, painful swelling in your face, hands, feet, genitals, buttocks, or upper airway.

Haegarda is a biologic and belongs to a drug class called C1 esterase inhibitors. Haegarda is not available in a biosimilar version.

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

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

The information below describes Haegarda’s typical dosage and other details about the drug.

Haegarda form

Haegarda comes as a kit containing powder in a single-dose vial. The powder is mixed with a liquid to form a solution that’s given as a subcutaneous injection.

Haegarda strengths

Haegarda comes in two strengths: 2,000 international units (IU) and 3,000 IU.

Typical dosages

The following information describes dosages that are commonly prescribed or recommended. 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 Haegarda to prevent HAE attacks in adults.

If your doctor prescribes Haegarda for HAE, your dosage will be based on your body weight in kilograms. For reference, 1 kilogram (kg) equals about 2.2 pounds (lb). Your doctor will calculate your dosage, which will be measured in IU per kg (IU/kg).

Haegarda’s typical dosage is 60 IU/kg. It’s given as a subcutaneous injection twice per week (once every 3–4 days).

For example, if you weigh 70 kg (about 154 lb), your dose of Haegarda will be 4,200 IU twice per week.

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

Children’s dosage

Haegarda is approved to prevent HAE attacks in children ages 6 years and older. The dosage is the same as the adult dosage. For details, see the “Dosage for HAE” section above.

Talk with your child’s doctor if you have questions about their dosage.

Long-term treatment

Haegarda is meant to be used as a long-term treatment. If you and your doctor determine that Haegarda is safe and effective for you, you’ll likely use it long term.

Before you start using Haegarda, your doctor will discuss your treatment plan with you.

The Haegarda dosage your doctor prescribes will depend on several factors. These include:

  • your body weight, which may change over time
  • the type and severity of the condition you’re using Haegarda to treat
  • other medical conditions you may have

Haegarda comes as a powder in a vial. It gets mixed with sterile water and is given as a subcutaneous injection.

Your doctor will give you your first dose. Then, they’ll show you or your caregiver how to inject the medication. You’ll use a syringe to draw up the correct dosage and give yourself a Haegarda injection. Make sure to use Haegarda according to the instructions from your doctor.

You’ll store Haegarda at room temperature — up to 86°F (30°C). Do not freeze Haegarda.

You can self-inject Haegarda into your abdomen or another site your doctor recommends. If you use your abdomen, do not inject Haegarda within 2 inches of your belly button.

Be sure to choose a different injection site each time you inject Haegarda. And avoid areas where your skin is tender, hard, irritated, or scarred. This will reduce your risk of injection-related side effects, such as bleeding or pain at the injection site.

If you have questions about how to use Haegarda, talk with your doctor or pharmacist. There are also step-by-step instructions and 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.

Haegarda works best if it’s used as scheduled. If you miss a dose, contact your doctor. They’ll let you know if you should inject the missed dose or wait and use the next scheduled dose.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or putting a note where you’ll see it, such as on your bathroom mirror or bedside table. You could also download a reminder app on your phone.

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

If you use more than the recommended amount of Haegarda

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

Is the dosage of Haegarda similar to the dosage of Berinert?

No, it is not similar. Although both Haegarda and Berinert are C1 esterase inhibitors prescribed for HAE attacks, their uses and dosages are different. Haegarda is approved to prevent HAE attacks and is given as a subcutaneous injection. Berinert is approved to treat HAE attacks after they happen and is given as an IV infusion.

Since the drugs are used differently, your doctor will prescribe the drug and the dosage that’s right for your condition.

To learn more about how Haegarda and Berinert compare, talk with your doctor.

How long does it take for Haegarda to start working?

Haegarda starts to work after your first dose. Because of how the drug works, you likely won’t feel it working in your body. It may take several doses to build up the amount of C1 esterase inhibitor in your body. Your doctor will 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 Haegarda treatment.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Haegarda 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 Haegarda without your doctor’s recommendation. If you have questions about the dosage of Haegarda that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Haegarda. These additional articles might be helpful:

  • More about Haegarda: For information about other aspects of Haegarda, refer to this article.
  • Drug comparison: To find out how Haegarda compares with Berinet or Cinryze, read this article.

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.