Icatibant (Firazyr)_Dosage, benefits & legal status
Also known as Firazyr, Sajazir, HOE 140, HOE-140, icatibant acetate
A self-injected decapeptide for acute swelling attacks in hereditary angioedema, generic in the US since 2019.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Icatibant (Firazyr)?
Plain language first. The technical label stays, but it never stands alone.Overview
In hereditary angioedema a missing control protein lets bradykinin build up, causing sudden swelling of the skin, gut or throat. One 30 mg shot under the skin blocks bradykinin's receptor and halves symptoms in a median of about 2 hours. It was approved in the EU in 2008 and the US in 2011, and US generics have been sold since 2019.
Icatibant is a ten-residue peptide, five of them non-natural, that blocks the bradykinin B2 receptor. Hoechst discovered it as HOE 140, Jerini developed it, Shire bought Jerini in 2008, and Takeda now sells it as Firazyr.
What it's used for
A prescription shot for acute attacks of hereditary angioedema in adults. Most people get an injection-site reaction, and it does not work for ACE-inhibitor swelling.
How does Icatibant (Firazyr) work?
What it does in the body, and where.Icatibant is a modified copy of bradykinin, the nine-residue peptide it blocks: D-arginine is added at the front and four positions are swapped for non-natural amino acids, so it fits the receptor without switching it on.
- 01Bradykinin in HAEHereditary angioedema comes from missing or faulty C1-esterase inhibitor, the protein that normally limits bradykinin production. Bradykinin widens blood vessels and is thought to cause the swelling, inflammation and pain of an attack.
- 02Blocking B2Icatibant competes with bradykinin for the B2 receptor with similar affinity and binds about 1,000 times more strongly to B2 than to B1. A 30 mg dose is predicted to block a bradykinin challenge for at least 6 hours.
- 03Short-livedProteases break it down within hours (half-life about 1.4 hours), so it treats the attack in front of it rather than preventing the next one.
A schematic of the compound's mechanism, not a diagnostic image.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
Hereditary angioedema attacks
FDA-approved- Human trialFAST-3: median 2.0 hours to a 50% fall in symptoms against 19.8 hours on placebo; almost complete relief in 8 against 36 hours.
- Human trialAcross trials, 93% of 987 attacks were treated with a single dose; throat attacks responded like other sites.
- No dataFAST-1 failed its primary endpoint, and only a secondary 4-hour score was significant.
Other swelling
tested-and-failed- Human trialACE-inhibitor angioedema, 121 patients randomised: no faster recovery than placebo (4.0 against 4.0 hours).
- No dataCOVID-19 trials were small, and their published analysis was post hoc and exploratory.
FAST-1 is often listed as a positive trial, but its primary endpoint failed (p=0.142); only a secondary 4-hour score was significant. It is not approved in the US for children; that is an EU indication. It does not treat ACE-inhibitor angioedema, where a randomised trial found no benefit, or allergic swelling, driven by histamine rather than bradykinin. COVID-19 use rests on small exploratory studies. HOE 140 is also a lab reagent in thousands of bradykinin papers that say nothing about the drug in patients. US orphan exclusivity ended in August 2018 and the first generic was approved in July 2019.
The published record
Papers and trials about Icatibant (Firazyr)
221 papers tagged human · 131 not reviews or lab · 29 clinical trial publications
33 registered trials · 15 with posted results
Furthest stage reached: Approved in the US
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count. 495 papers and 33 trials indexed in detail.
At a glance
Four things to know about Icatibant (Firazyr)
Evidence
FDA-approved
Category
Immune support
Common vial
Varies
Half-life
About 1.4 hours
How much, and do you cycle it?
The range, and whether you take breaks.30 mg per attack (label), as needed, up to 3 doses in 24 hours. On demand, for attacks only FDA label
Used only when an attack starts, not on a schedule. Preventing attacks needs a different drug.
How long does it stay in the body?
The half-life, and where the figure comes from.About 1.4 hoursFDA label
1.4 +/- 0.4 hours after 30 mg under the skin. Peak at about 45 minutes, bioavailability about 97%. Broken down by proteases, with under 10% excreted unchanged. Exposure roughly doubles in older adults.
Source: Firazyr prescribing information section 12.3; Firazyr EU SmPC (1 to 2 hours)
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
How do you store it?
Before mixing, and after.Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.
Unmixed lyophilized Icatibant (Firazyr) keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.
What are the side effects and cautions?
Known cautions and warnings for this compound.Solubility, computed: 50% charged residues, 50% hydrophobic. Water usually sufficient.
A first-pass rule from peptide manufacturers' guidance. It does not account for disulfide bridges, salt form or how the powder was dried, and it predicts what should be easy rather than what will happen in your vial.
Who should avoid it
- None on the US label
- Taking an ACE inhibitor: icatibant may blunt its blood-pressure effect, and the trials excluded ACE-inhibitor users
- Acute heart ischaemia, or the weeks after a stroke: the EU label advises caution
- Under 18 in the US: not established (the EU allows it from age 2)
- Pregnancy: lower embryo survival in rabbits at high doses
Stop and get help
- Any swelling of the throat or tongue, or trouble breathing or swallowing: go to emergency care even after injecting
- Chest pain after a dose
- Spreading hives or other signs of a severe allergic reaction
Common effects
- Injection-site reactions in 97% against 33% on placebo: redness, swelling, burning, itching and pain
- Fever in 4% and raised liver enzymes in 4%, against none on placebo
- Dizziness in 3%
- 93% of attacks needed only one dose
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Icatibant (Firazyr) approved?
And where the numbers on this page come from.Yes. Icatibant (Firazyr) is FDA approved and available on prescription in the United States. It is also approved in the European Union and Japan.
- Approval statusFDA-approved
- RouteUnder the skin (subcutaneous), self-injected
- Checked12 October 2026
- Approved outside the USEuropean Union, Japan: Authorised in the EU on 11 July 2008, with use from age 2 since October 2017; current holder Takeda. Approved in Japan for adults in September 2018. Also approved in the US.This does not change the United States position above.
- DoseFrom the drug label. The manufacturer tested this range and a regulator reviewed it.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesFirazyr prescribing information (DailyMed, revised 6/2025)Drugs@FDA, NDA 022150FDA summary review, NDA 022150ClinicalTrials.gov, FAST-3 posted results (NCT00912093)ClinicalTrials.gov, FAST-1 posted results (NCT00097695)ClinicalTrials.gov, FAST-2 posted results (NCT00500656)Cicardi M et al., New England Journal of Medicine 2010;363:532-541Hock FJ et al., British Journal of Pharmacology 1991;102:769-773EMA, Firazyr EPARJ Allergy Clin Immunol Pract 2017;5:1402-1409, icatibant in ACE-inhibitor angioedema
What has happened recently
FDA-approved on 25 August 2011 (NDA 022150) for acute attacks of hereditary angioedema in adults 18 and older, after an April 2008 action letter that did not approve it; self-injection is allowed after training. The first US generic (Teva) was approved on 15 July 2019, followed by Fresenius Kabi and Cipla in 2020 and others since. The EU authorised Firazyr on 11 July 2008 and extended it to children from age 2 in October 2017. Japan approved it for adults in September 2018. Takeda holds the brand after buying Shire in 2019.
You can compare this against the whole library, or read how to check a seller.
What else is like Icatibant (Firazyr)?
Others in Immune support, side by side.If you're weighing Icatibant (Firazyr), it's worth reading Imunofan, Mifamurtide (Mepact), and P140 (forigerimod) in the same class.
A self-injected decapeptide for acute swelling attacks in hereditary angioedema, generic in the US since 2019.
- Dose
- 30 mg per attack (label)
- How often
- As needed, up to 3 doses in 24 hours
A Russian rework of thymopentin, with one amino acid added at each end.
- Dose
- 50 mcg per dose
- How often
- Every other day, in courses
A synthetic bacterial cell-wall fragment that activates macrophages, approved in Europe for osteosarcoma but not in the US.
- Dose
- 2 mg/m2 per infusion (EU label)
- How often
- Twice weekly for 12 weeks, then weekly for 24 weeks
An experimental lupus peptide whose pivotal trial missed its endpoint in 2018.
- Dose
- 200 mcg every 4 weeks (every trial to date)
- How often
- Every 4 weeks
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
Sources
- Firazyr prescribing information (DailyMed, revised 6/2025)(2025)30 mg SC per attack, repeat after 6 hours, maximum 3 in 24 hours; adults only. FAST-3: median 2.0 against 19.8 hours to 50% symptom reduction. Injection-site reactions 97% against 33%. Half-life 1.4 hours.
- Drugs@FDA, NDA 022150(2024)Approved 25 August 2011, new molecular entity, priority review, orphan.
- FDA summary review, NDA 022150(2011)Explains the 2008 action and the role of FAST-3. FAST-1 showed a numerical trend that was not statistically significant.
- ClinicalTrials.gov, FAST-3 posted results (NCT00912093)(2011)98 adults, quadruple-masked against placebo: primary symptom relief 1.5 against 18.5 hours (p<0.001).
- ClinicalTrials.gov, FAST-1 posted results (NCT00097695)(2009)Primary endpoint missed: median 2.5 against 4.6 hours to symptom relief (p=0.142).
- ClinicalTrials.gov, FAST-2 posted results (NCT00500656)(2009)Against oral tranexamic acid: median 2.0 against 12.0 hours to relief (p<0.001).
- Cicardi M et al., New England Journal of Medicine 2010;363:532-541(2010)FAST-1 and FAST-2 report; early rescue medication may have obscured benefit in the placebo trial.
- Hock FJ et al., British Journal of Pharmacology 1991;102:769-773(1991)Discovery paper for Hoe 140 at Hoechst: Ki 0.8 nM at guinea-pig ileum B2 receptors, no effect on B1 responses.
- EMA, Firazyr EPAR(2024)Authorised 11 July 2008; holder Takeda; paediatric use from age 2 added in 2017.
- J Allergy Clin Immunol Pract 2017;5:1402-1409, icatibant in ACE-inhibitor angioedema(2017)121 patients randomised: time to meeting discharge criteria 4.0 against 4.0 hours (P=.63); no more effective than placebo.
Beyond these, 528 records are indexed. Browse the records