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Ecallantide (Monograph)

Brand name: Kalbitor
Drug class: Kallikrein Inhibitors
Molecular formula: C305H442O91S8
CAS number: 460738-39-9

Medically reviewed by on Jan 31, 2022. Written by ASHP.


  • Potential for severe hypersensitivity reactions (e.g., anaphylaxis). (See Sensitivity Reactions under Cautions.)

  • Clinicians should be aware of the similarity between symptoms of a hypersensitivity reaction and a hereditary angioedema (HAE) attack; administer only in a setting equipped to monitor and treat hypersensitivity reactions and HAE attacks.

  • Do not administer to patients with known hypersensitivity to ecallantide.


Selective, reversible plasma kallikrein inhibitor; biosynthetic (recombinant DNA origin) protein.

Uses for Ecallantide

Hereditary Angioedema

Treatment of acute angioedema attacks in patients with hereditary angioedema (HAE).

Designated an orphan drug by FDA for this use.

Ecallantide Dosage and Administration


  • Administer only under supervision of qualified clinicians experienced in management of anaphylaxis and HAE and in a setting with appropriate and readily available medical support (e.g., antihistamines, epinephrine, corticosteroids) to manage such conditions.

  • Monitor for possible hypersensitivity reactions (e.g., anaphylaxis) for an appropriate period of time (i.e., at least 1 hour) after administration.

  • If persistent HAE attack symptoms are present, assess patient carefully prior to administration of second dose of ecallantide to determine whether symptoms represent HAE attack or hypersensitivity reaction. (See Sensitivity Reactions under Cautions.)


Sub-Q Administration

Administer by sub-Q injection.

Vials are for single use only.

To prepare a 30-mg dose: Withdraw 1 mL of ecallantide injection from a vial containing 10 mg/mL of the drug into an appropriately sized syringe using a large-bore needle. Perform procedure with each of 3 vials to prepare total dose (3 syringes each containing ecallantide 10 mg).

Prior to administration, replace large-bore needle on each syringe with a 27-gauge needle for sub-Q injection.

Observe strict aseptic technique; drug vials contain no preservative.

Inject sub-Q into abdomen, thigh, or upper arm. Use same anatomic site for all 3 injections or select different sites; separate injections administered at same site by 2 inches (5 cm) and inject away from site of HAE attack. Rotation of injection sites not necessary.

If a second 30 mg-dose is required, may use same anatomic site as for initial dose or select different site.



Hereditary Angioedema

Patients ≥16 years of age: 30 mg. May administer second 30-mg dose within 24 hours after initial dose for persistent HAE attack symptoms.

Prescribing Limits


Hereditary Angioedema

Patients ≥16 years of age: Maximum 60 mg (i.e., two 30-mg doses) in 24-hour period.

Special Populations

Hepatic Impairment

No specific dosage recommendations.

Renal Impairment

No specific dosage recommendations.

Geriatric Patients

Select dosage with caution; usually initiate therapy at low end of dosage range. (See Geriatric Use under Cautions.)

Cautions for Ecallantide


  • Known hypersensitivity to ecallantide or any ingredient in formulation.


Sensitivity Reactions

Risk of severe hypersensitivity reactions (e.g., chest discomfort, flushing, pharyngeal edema, pruritus, rhinorrhea, sneezing, nasal congestion, throat irritation, urticaria, wheezing, hypotension), including anaphylaxis. Monitor patient; such reactions usually occur within first hour following drug administration. (See General under Dosage and Administration.)

Because symptoms of hypersensitivity can resemble those of acute HAE attacks, carefully consider treatment method. Use of medical support for anaphylaxis (e.g., epinephrine, antihistamines, corticosteroids) may be required.

Response to antihistamine and sympathomimetic therapy may distinguish between hypersensitivity reaction (a histamine-mediated event) and acute HAE attack (bradykinin-mediated event); hypersensitivity reactions likely to respond to this type of medical intervention, while HAE attack symptoms likely to be resistant.


Development of anti-ecallantide antibodies reported occasionally. Neutralizing antibodies to ecallantide also reported, as were IgE antibodies to ecallantide and yeast (Pichia pastoris).

Seroconversion rate increases with number of doses received. Risk of hypersensitivity reactions may be increased in patients with anti-ecallantide antibodies.

Long-term effects of antibody formation not known.

Specific Populations


Category C.


Not known whether ecallantide is distributed into milk. Use caution.

Pediatric Use

Safety and efficacy not established in children <16 years of age.

Geriatric Use

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults; use with caution due to greater frequency of decreased hepatic, renal, and/or cardiac function and of concomitant disease and drug therapy in the elderly.

Hepatic Impairment

Safety and efficacy not established.

Renal Impairment

Safety and efficacy not established.

Common Adverse Effects

Headache, nausea, diarrhea, pyrexia, injection site reactions, nasopharyngitis.

Interactions for Ecallantide

No formal drug interaction studies to date.

Ecallantide Pharmacokinetics



Approximately 90%.


Peak plasma concentrations attained within 2–3 hours following single 30-mg sub-Q dose.



Not known whether distributed into milk.


Elimination Route

Excreted in urine; since drug is a small protein, metabolic catabolism (or degradation) also likely.


Approximately 2 hours.

Special Populations

Pharmacokinetics not studied in patients with hepatic or renal impairment.





2–8°C. Protect from light.

Vials removed from refrigerator should be stored below 30°C and used within 14 days or returned to refrigeration until use.


  • Prevents binding of kallikrein to target receptor.

  • Inhibits kallikrein activity and prevents conversion of high-molecular weight kininogen to bradykinin.

  • Reduced plasma concentrations of bradykinin result in reduction of bradykinin-mediated HAE attack symptoms (e.g., swelling, inflammation, pain).

  • Prolongation of thrombin time (>30 seconds) reported rarely; however, no clinically important effects on coagulation parameters (i.e., aPTT, PT) in patients with HAE receiving the drug by sub-Q injection. No abnormal patterns or increased risk of bleeding or thrombosis.

  • No clinically important effects on QTc interval, heart rate, or other ECG measurements.

Advice to Patients

  • Importance of providing a medication guide to the patient each time the drug is administered. Importance of discussing potential risks and benefits of therapy with the patient; importance of the patient reading the medication guide prior to initiation of therapy and before subsequent treatment.

  • Importance of differentiating serious hypersensitivity reactions to ecallantide from symptoms of an HAE attack.

  • Risk of hypersensitivity reactions, including anaphylaxis. Importance of immediately informing clinician of possible hypersensitivity symptoms (e.g., shortness of breath, cough, chest tightness, trouble breathing, dizziness, fainting, irregular heartbeat, anxiety, reddening of the face, itching, hives, feeling of warmth, swelling of the throat or tongue, throat tightness, hoarse voice, trouble swallowing, runny nose, sneezing). Inform patients that most reactions occur within 1 hour following sub-Q injection of ecallantide. Importance of not administering ecallantide to patients with a history of hypersensitivity to the drug.

  • Importance of women informing their clinician if they are or plan to become pregnant or plan to breast-feed.

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs and dietary or herbal supplements.

  • Importance of informing patients of other important precautionary information. (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.



Dosage Forms


Brand Names



Injection, for subcutaneous use

10 mg/mL



AHFS DI Essentials™. © Copyright 2023, Selected Revisions January 31, 2022. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

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