Ross is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.
Lindsay Cook, PharmD is a board-certified consultant pharmacist.
Firazyr (icatibant ) is a prescription medication used for the acute treatment of hereditary angioedema (HAE) attacks (flare-ups) in adults.
As a bradykinin receptor antagonist, Firazyr blocks bradykinin B2 receptors (binding sites). By blocking bradykinin B2 receptors, a type of protein called bradykinin—that widens blood vessels—can’t attach to these binding sites to cause the typical HAE symptoms of swelling and pain.
Firazyr is available as an injectable to be given under the skin (subcutaneous).
Brand Name(s): Firazyr
Therapeutic Classification: Immune modulator
Controlled Substance: N/A
Firazyr is a prescription treatment option for HAE attacks. Although HAE is a serious genetic medical condition, it is rare—affecting 1 in 50,000 people in the United States. Many people with HAE will start experiencing symptoms during childhood.
Some common HAE symptoms include a non-itchy rash and swelling of the face, arms, legs, hands, feet, digestive system, and throat during a flare-up. If you experience swelling in the digestive system, additional symptoms may include severe stomach upset, nausea, and vomiting. As for swelling of the throat, you can have trouble breathing, which can be life-threatening. Without treatment, these flare-ups can occur every one to two weeks and last for three to four days with each attack.
There are three types of HAE:
In general, in all three types of HAE, a high amount of bradykinin is due to a modified gene made of deoxyribonucleic acid (DNA).
The following are general directions to use Firazyr. If you have any questions, please ask your healthcare provider or pharmacist. You will take your medication once you recognize the onset of an HAE attack.
If your HAE symptoms are different or Firazyr isn’t providing enough relief, get medical help right away. If your HAE symptoms include swelling of your throat or tongue, seek immediate medical attention—even after the first Firazyr dose.
Firazyr is a non-controlled prescription medication. As a result, your healthcare provider can authorize refills for up to one year from the originally written date on the prescription. However, your healthcare provider might give you fewer refills so they can regularly visit with you and monitor how you are doing on Firazyr.
After you receive Firazyr from the pharmacy, store the medication between 36 degrees to 77 degrees Fahrenheit (F). This is a wide range that includes standard refrigerator and room temperature conditions. However, don’t freeze this medication.
If you plan to travel with Firazyr, be prepared by knowing the regulations of your final destination. Keep the medication in its original container or packaging—with your name—from the pharmacy. Also, have a copy of your Firazyr prescription readily available.
Angiotensin-converting enzyme inhibitors (ACE inhibitors) are used for several medical conditions, including high blood pressure. Although rare, a severe side effect of ACE inhibitors is angioedema.
Off-label use means a drug is prescribed for a medical condition that it is not approved by the Food and Drug Administration (FDA) to treat. Icatibant has been used off-label for ACE inhibitor-induced angioedema. However, effectiveness data is conflicting.
Within 30 to 120 minutes, you should notice some symptom relief. However, keep in mind that Firazyr helps prevent the worsening of HAE symptoms. Unfortunately, swelling already present—before the initial injection—will still take some time to go away.
This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.
The most common side effects are the following injection site reactions—which are side effects in the area where you injected the medication:
Other common side effects include:
Firazye does not typically cause severe side effects. However, you should get medical help immediately if any of your HAE symptoms involve swelling of the throat. Tell your healthcare provider if your symptoms bother you or don’t go away.
Daily injections of Firazyr at high doses in rats and dogs were linked to wasting away of ovaries, uterus, and testicles.
In nonhuman studies, Firazyr also caused negative effects on the heart during or shortly after a heart attack, unstable angina (chest pain), or stroke. Since there is little safety data on Firazyr in humans for these situations, the manufacturer recommends weighing the benefits and risks of using this medication during or shortly after these medical events.
Firazyr may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).
It is very important that your doctor check your progress closely to make sure that this medicine is working properly and to decide if you should continue to receive it.
During a laryngeal (throat) HAE attack, you may have shortness of breath or troubled breathing. If you have a laryngeal HAE attack, inject this medicine and go to the nearest hospital or emergency clinic right away.
This medicine may cause severe tenderness and pain at the site of injection. Contact your doctor right away if you notice any of these side effects at the injection site: bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth.
This medicine may make you dizzy, drowsy, or tired. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Using Firazyr during pregnancy isn’t linked to negative effects on the fetus.
As for nursing, there is little safety data about Firazyr’s effects on nursing babies. Weigh the benefits and risks with your healthcare provider before using this medication while breastfeeding.
Firazyr is typically used on an as-needed basis during an HAE attack. There are usually no scheduled doses to miss.
Once you notice an onset of an HAE attack, don’t delay using Firazyr. The medication is meant to prevent the worsening of an HAE attack. Early use of Firazyr is very important to control your symptoms.
The side effects at a high dose of 90 milligrams were similar to the standard one-time injection of 30 milligrams when given under the skin. However, another possible side effect might include low blood pressure.
If you think you or someone else may have overdosed on Firazyr, call a healthcare provider or the Poison Control Center (800-222-1222).
If someone collapses or isn't breathing after taking Firazyr, call 911 immediately.
It is very important that your doctor check your progress closely to make sure that this medicine is working properly and to decide if you should continue to receive it.
During a laryngeal (throat) HAE attack, you may have shortness of breath or troubled breathing. If you have a laryngeal HAE attack, inject this medicine and go to the nearest hospital or emergency clinic right away.
This medicine may cause severe tenderness and pain at the site of injection. Contact your doctor right away if you notice any of these side effects at the injection site: bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth.
This medicine may make you dizzy, drowsy, or tired. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Use caution when taking ACE inhibitors. Firazyr might lower the effectiveness of ACE inhibitors. ACE inhibitors are used to lower blood pressure and include therapies such as Accupril (quinapril), Altace (ramipril), Zestril (lisinopril), and others.
Firazyr is the only bradykinin B2 receptor antagonist. However, the following are other medication options for treating an HAE flare-up:
Although experts consider all four on-demand options effective and safe, there are some differences to keep in mind. Berinert and Ruconest are both given as an infusion through the vein. As for Kalbitor, like Firazyr, it is conveniently given under the skin. However, due to the potential of a severe allergic reaction, you will need to go to the healthcare provider’s office to receive Kalbitor. Firazyr is the most convenient option compared with the other three acute HAE treatment choices.
These medications are not typically used together. However, some people might benefit from more than one of these acute options in certain cases. If you have questions, talk with your healthcare provider.
Firazyr isn’t available at your local retail pharmacy. Your healthcare provider may need to send a prescription to a specialty pharmacy.
Although there is a generic version of Firazyr, both Firazyr and its generic are specialty medications. Therefore, it is typically expensive. If you are concerned about the cost, talk with your specialty pharmacist. Takeda also has a program called OnePath that can offer some copay assistance options. If cost is a concern for the Firazyr brand-name product, consider calling 1-866-888-0660.
Firazyr’s prescribing information does not list severe allergic reactions as a possible side effect.
In addition to the physical symptoms, living with HAE can understandably take a toll on your emotions. A mental health professional can talk with you about some coping strategies to help change how you feel, think, or react to living with HAE.
It’s also important to have a strong support network with family, friends, and support groups. Consider taking the first step by sharing your medical condition with loved ones so that, if a flare-up occurs, your loved ones won’t feel as worried or afraid.
It’s also important to prepare for an HAE attack. Always have your Firazyr medication nearby to use if you sense an HAE flare-up immediately.
Staying in touch with your healthcare team will help address any questions or concerns that you may have.
Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some drug content, as indicated on the page.
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Food and Drug Administration. Firazyr label.
Busse PJ, Christiansen SC, Riedl MA, et al. US HAEA Medical Advisory Board 2020 guidelines for the management of hereditary angioedema.The Journal of Allergy and Clinical Immunology: In Practice. 2020. doi:10.1016/j.jaip.2020.08.046
Baş M, Greve J, Stelter K, et al. A randomized trial of icatibant in ACE-inhibitor-induced angioedema. N Engl J Med. 2015; 372:418-425. doi:10.1056/NEJMoa1312524
Straka BT, Ramirez CE, Byrd JB, et al. Effect of bradykinin receptor antagonism on ACE inhibitor-associated angioedema. Translational and Clinical Immunology. 2016. doi:10.1016/j.jaci.2016.09.051
Sinert R, Levy P, Bernstein JA, et al. Randomized trial of icatibant for angiotensin-converting enzyme inhibitor-induced upper airway angioedema. The Journal of Allergy and Clinical Immunology: In Practice. 2017. doi:10.1016/j.jaip.2017.03.003
Food and Drug Administration. Kalbitor label.
Food and Drug Administration. Ruconest label.
Food and Drug Administration. Berinert label.
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