Acquired Angioedema Medication

The goals of pharmacotherapy for acquired angioedema are to reduce morbidity and to prevent complications. Medication may be used for acute or preventive treatment.

In Europe, purified C1 inhibitor (C1-INH) has been available for the treatment of acute attacks for decades, but it has not been available in the United States until recently. In October 2008, the US Food and Drug Administration (FDA) approved the use of C1-INH (Cinryze) at a dose of 1000 units IV 2-3 times/wk for prophylaxis to prevent attacks. In October 2009, the FDA approved C1-INH (Berinert) at a dose of 20 units/kg IV for the treatment of acute abdominal and facial angioedema attacks in adolescents and adults with HAE. Berinert was also approved for acute treatment of laryngeal attacks in January 2012.

In acquired angioedema, therapy for acute attacks may be aborted with C1-INH concentrates or, if those are unavailable, fresh-frozen plasma. However, rapid catabolism of C1-INH occurs in acquired angioedema, so higher doses of C1-INH plasma concentrate may be needed.

In December 2009, ecallantide (Kalbitor), a kallikrein inhibitor, at a dose of 30 mg SC was approved for the treatment of acute attacks.

In August 2011, icatibant (Firazyr), a selective bradykinin B2 receptor antagonist, was approved for treatment of acute attacks of HAE in adults at a dose of 30 mg SC in the abdominal area.

Androgens, such as danazol or stanozolol, may be beneficial in acquired angioedema type I but are of no value in acquired angioedema type II (AAE-II). Prostate cancer and pregnancy preclude the use of androgens.

Antifibrinolytics, such as epsilon-aminocaproic acid and tranexamic acid, have been found to be more effective for long-term prophylaxis in those with acquired angioedema.

Immunosuppressive therapy directed toward decreasing autoantibody production may be of value in patients with acquired angioedema type II, which may be accomplished by the use of plasmapheresis with cyclophosphamide.

Class Summary

These agents are used to improve the clinical aspects of the disease.^[4]

Fresh Frozen Plasma

Infuse prior to airway manipulation (eg, dental extraction) to prevent angioedema. Administering 2 units of fresh frozen plasma (FFP) sustains complement control and prevents the development of angioedema. Improved screening programs greatly reduce risk of hepatitis. FFP is not recommended for treatment of acute attacks.

Class Summary

Some agents in this class have potent immunosuppressive activity.

Cyclophosphamide

Cyclophosphamide is chemically related to nitrogen mustards. As an alkylating agent, the mechanism of action of the active metabolites may involve cross-linking of DNA, which may interfere with growth of normal and neoplastic cells.

Class Summary

These concentrates are used in the acute treatment of angioedema. They have recently been approved by the US FDA for routine prophylaxis against angioedema attacks and as treatment for acute attacks.

C1-inhibitor, human (Cinryze)

C1-INH is a normal constituent of human blood and is one of the serine proteinase inhibitors (serpins). It regulates activation of the pathway for complement and intrinsic coagulation, and it regulates the fibrinolytic system.

This agent is available as a sterile, lyophilized preparation derived from human plasma. Specific activity is 4-9 U/mg protein. One unit corresponds to the mean quantity of C1 inhibitor present in 1 mL of normal fresh plasma. It is indicated for routine prophylaxis against angioedema attacks in adolescents and adults with hereditary angioedema.

C1-INH some of the missing protein, but the half-life in the circulation is short. Approved use is 1000 units biweekly, with the possibility of a third dose of 1000 units/wk if needed. Although FDA approval is for prophylaxis only at this time, this agent has been available for the treatment of acute attacks in Europe for decades and has an excellent safety profile.

C1 esterase inhibitor, human (Berinert)

This agent is a serine proteinase inhibitor found in human blood that regulates activation of the kinin system, complement pathway, intrinsic coagulation system, and fibrinolytic system. It binds to and neutralizes substrates that activate these systems, thereby suppressing activity. It is available as a pasteurized, lyophilized preparation derived from purified human plasma. One unit corresponds to the mean quantity of C1 inhibitor present in 1 mL of normal fresh plasma. C1 esterase inhibitor is indicated for acute laryngeal, abdominal, and facial angioedema attacks in adolescents and adults with HAE.

Class Summary

These agents have specific kallikrein inhibitor activity, resulting in bradykinin reduction. They are useful for treating acute episodic attacks. The package insert carries a black box warning because a small subset of patients may have anaphylactic reactions to the drugs. They must be administered by medical personnel capable of treating anaphylaxis.

Ecallantide (Kalbitor)

A human plasma kallikrein inhibitor, ecallantide binds to plasma kallikrein and blocks its binding site. It reduces the conversion of kininogen to bradykinin. This agent is indicated for acute attacks of HAE. It is available as an injectable solution; 10 mg/mL per single-use vial.

Class Summary

Bradykinin receptor antagonists such as icatibant inhibit bradykinin from binding the B2 receptor and thereby treat the clinical symptoms of an acute attack. Recommended dose of icatibant is 30 mg SC in the abdominal area. It is available as a single-use, prefilled syringe, which delivers a dose of 30 mg (10 mg/mL).

Icatibant (Firazyr)

Bradykinin B2 receptor antagonist indicated for acute attacks of hereditary angioedema (HAE).

Class Summary

These agents have immunosuppressive properties.

Danazol

Danazol increases levels of the C4 component of complement and prevents attacks associated with angioedema.

Stanozolol

A synthetic androgen with immunosuppressive properties, stanozolol increases levels of C1 esterase inhibitor and C4 component of the complement. It is no longer available in the United States.

Class Summary

Antifibrinolytic agents act through the inhibition of plasmin. They tend to be more effective than androgens for prophylaxis.^[3]

Aminocaproic acid (Amicar)

Aminocaproic acid is a lysine analog that inhibits fibrinolysis via inhibition of plasminogen activator substances and, to a lesser degree, through antiplasmin activity.

This agent is widely distributed. Half-life is 1-2 h. Peak effect occurs within 2 h. Hepatic metabolism is minimal. It can be used PO or IV.

Tranexamic acid (Cyklokapron, Lysteda)

An alternative to aminocaproic acid, tranexamic acid inhibits fibrinolysis by displacing plasminogen from fibrin.