What is Firazyr, and how does it work?

Firazyr is a medicine used to treat acute attacks of hereditary angioedema (HAE) in adults 18 years and older. It is not known if Firazyr is safe or effective for children under 18 years of age.

What are the side effects of Firazyr?

The most common side effects of Firazyr include:

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all of the possible side effects of Firazyr. For more information, ask your healthcare provider or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the dosage for Firazyr?

Recommended Dosing

  • The recommended dose of Firazyr is 30 mg administered by subcutaneous (SC) injection in the abdominal area.
  • Additional doses may be administered at intervals of at least 6 hours if response is inadequate or if symptoms recur.
  • No more than 3 doses may be administered in any 24 hour period.

Administration Instructions

  • Firazyr should be inspected visually for particulate matter and discoloration prior to administration.
  • The drug solution should be clear and colorless. Do not administer if the product contains particulates or is discolored.
  • Attach the provided 25 gauge needle to the syringe hub and screw on securely.
  • Do not use a different needle.
  • Disinfect the injection site and administer Firazyr by subcutaneous injection over at least 30 seconds.
  • Patients may self-administer Firazyr upon recognition of symptoms of an HAE attack after training under the guidance of a healthcare professional.

What drugs interact with Firazyr?

ACE Inhibitors

  • Firazyr is a bradykinin B2 receptor antagonist and thereby has the potential to have a pharmacodynamic interaction with ACE inhibitors where Firazyr may attenuate the antihypertensive effect of ACE inhibitors.
  • Clinical trials to date have excluded subjects taking ACE inhibitors.

Is Firazyr safe to use while pregnant or breastfeeding?

  • Available data from published literature and the pharmacovigilance database with Firazyr (icatibant) use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes.
  • There are no data on the presence of icatibant in human milk, the effects on the breastfed infant, or the effects on milk production.
  • Icatibant and the M2 metabolite were found in rat milk following subcutaneous administration of icatibant (see Data). When a drug is present in animal milk, it is likely that the drug will be present in human milk.
  • However, systemic absorption of icatibant in infants is not expected after oral exposure through breast milk.
  • The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Firazyr and any potential adverse effects on the breastfed child from Firazyr or from the underlying maternal condition.


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Firazyr is a medicine used to treat acute attacks of hereditary angioedema (HAE) in adults 18 years and older. It is not known if Firazyr is safe or effective for children under 18 years of age.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 10/14/2020
All sections courtesy of the U.S. Food and Drug Administration