Pronunciation: KAL-bi-tor
Generic name: ecallantide [ e-KAL-an-tide ]
Dosage form: injection (10mg/mL)
Drug class: Hereditary angioedema agents

Medically reviewed by Melisa Puckey, BPharm. Last updated on Jun 26, 2025.

What is Kalbitor?

Kalbitor (ecallantide) is used to treat attacks of hereditary angioedema (an immune system disorder) to help reduce symptoms. Kalbitor is administered as three injections under the skin (subcutaneous injections) by a healthcare professional. This medicine is for use in adults and children at least 12 years old.

In clinical trials EDEMA3 (NCT00262080) and EDEMA4 (NCT00457015) at 4 hours, patients treated with Kalbitor had reduced hereditary angioedema (HAE) symptoms compared to patients treated with placebo. HAE symptoms were measured using the Mean Symptom Complex Severity (MSCS) score and the Treatment Outcome Score (TOS),

Kalbitor injection is not a cure for hereditary angioedema.

How does Kalbitor work?

Kalbitor works by blocking kallikrein, a type of enzyme that plays a crucial role in dilating blood vessels and increasing fluid leaking from capillaries. Blocking kallikrein reduces levels of bradykinin, the peptide that causes swelling during HAE attacks. 

Kalbitor mechanism of action is as a plasma kallikrein inhibitor.

What is hereditary angioedema?

Hereditary angioedema (HAE) is a rare genetic disorder characterized by sudden and severe swelling in various parts of the body, including the face, hands, abdomen, and airways. The genetic disorder results in reduced activity or quantity of the C1 esterase inhibitor protein, which leads to uncontrolled release of bradykinin, a molecule that causes the localized edema and painful swelling. Unlike allergic swelling, HAE is not triggered by allergens and does not respond to antihistamines or epinephrine.

Kalbitor side effects

Common Kalbitor side effects

Common Kalbitor side effects may include:

• headache;
• nausea, diarrhea;
• fever;
• stuffy nose, sore throat; or
• skin reactions where the medicine was injected (redness, rash, itching, bruising, swelling).

Serious Kalbitor side effects

Anaphylaxis has been reported after administration of this medicine. Tell your caregivers right away if you have any of these signs of an allergic reaction to Kalbitor within 1 hour after receiving your injection:

• chest pain or tightness, fast or weak heartbeat;
• wheezing, cough, throat irritation, trouble breathing;
• hoarse voice, tight feeling in your throat, trouble swallowing;
• swelling of your lips, tongue, or throat;
• swelling or redness in your face;
• itching, rash, or hives;
• flushing (warmth, redness, or tingly feeling);
• sneezing, runny or stuffy nose; or
• dizziness, feeling like you might pass out.

An allergic reaction to ecallantide can cause symptoms that are similar to the signs of hereditary angioedema. Your caregivers will watch you closely and will quickly treat an allergic reaction to ecallantide.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

You should not be treated with Kalbitor injection if you are allergic to ecallantide. Ecallantide can cause a serious allergic reaction (anaphylaxis) within 1 hour after receiving an injection. Symptoms include wheezing, cough, trouble breathing or swallowing, itching, hives, dizziness, fainting, or swelling in your face or throat. Tell your doctor if you have a history of any type of allergy.

In an emergency situation, it may not be possible to tell your caregivers about your health conditions. Make sure any doctor caring for you afterward knows you have received this medicine.

Before receiving this medicine

You should not be treated with Kalbitor injection if you are allergic to ecallantide.

If possible, before you receive Kalbitor injection, tell your doctor if you have a history of any type of allergy.

It is not known whether Kalbitor injection will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether the active ingredient ecallantide passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breastfeeding a baby.

In an emergency situation, it may not be possible to tell your caregivers if you are pregnant or breastfeeding. Make sure any doctor caring for your pregnancy or your baby knows you have received this medicine.

How is Kalbitor given?

Kalbitor is administered as a subcutaneous injection under the skin. A healthcare provider will administer this injection where there is appropriate medical support available.

You will be watched closely after receiving your injection to make sure you do not have an allergic reaction to the medication.

Kalbitor is usually given as 3 injections. If you still have symptoms of the angioedema attack, more injections may be given within 24 hours.

Kalbitor dosing information

Usual adult Kalbitor dose: 30 mg subcutaneously in three 10 mg injections; may repeat an additional 30 mg within 24 hours if attack persists.

Usual pediatric dose 12 years and older: 30 mg subcutaneously in three 10 mg injections; may repeat an additional 30 mg within 24 hours if attack persists.

What happens if I miss a dose?

Because you will receive Kalbitor in a medical setting, you are not likely to miss a dose.

What happens if I overdose?

Since this medicine is given by a healthcare professional in a medical setting, an overdose is unlikely to occur and would be treated quickly.

What should I avoid after receiving this medicine?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect Kalbitor?

Other drugs may interact with ecallantide, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Kalbitor Prescribing Information

HCPs and patients often use the Kalbitor Prescribing Information for more detailed information about this medicine. The Kalbitor Prescribing Information contains more comprehensive information on Indications and Usage, Dosage and Administration, Clinical Pharmacology, Clinical Studies, Drug Interaction, and more. Discuss any medical questions you have with your HCP (health care professional). This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

The Prescribing Information is sometimes called Kalbitor Package Insert or FDA label.

Ingredients

Active Ingredient: ecallantide

Inactive ingredients: disodium hydrogen orthophosphate (dihydrate), monopotassium phosphate, potassium chloride, sodium chloride in water for injection.

Kalbitor manufacturer

Kalbitor manufacturer is Takeda Pharmaceuticals U.S.A., Inc.
Lexington, MA 02421

Kalbitor Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Kalbitor.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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