Icatibant: Uses, Mechanism, and Side Effects

For people living with hereditary angioedema, a sudden attack of swelling can be frightening and disruptive. Icatibant is a prescription treatment designed specifically to interrupt these acute episodes in adults.

Key takeaways

• Icatibant is approved under the brand name SAJAZIR for acute hereditary angioedema (HAE) attacks in adults 18 and older.
• It works by blocking the bradykinin B2 receptor, countering the swelling-causing effects of bradykinin.
• The label does not carry a boxed warning.
• At least 44 clinical trials have studied icatibant, including completed Phase 3 and Phase 4 studies in HAE.
• FAERS reports are dominated by the treated condition itself (hereditary angioedema) along with dosing and weight-related entries, reflecting reporting patterns rather than confirmed side effect rates.

What Icatibant Is

Icatibant is a bradykinin B2 receptor antagonist. In hereditary angioedema, a missing or malfunctioning protein called C1-esterase-inhibitor allows a biological cascade to overproduce bradykinin, a substance that causes blood vessels to dilate. This buildup of bradykinin is thought to drive the localized swelling, inflammation, and pain characteristic of HAE attacks. Icatibant works by competitively blocking the receptor that bradykinin would otherwise activate, interrupting this process.

What Icatibant Is Approved For

Icatibant, marketed as SAJAZIR, is indicated for treating acute attacks of hereditary angioedema in adults aged 18 and older. The label does not include a boxed warning.

What the Evidence Shows

Icatibant has been studied in at least 44 registered clinical trials. A completed Phase 4 trial evaluated the efficacy, safety, and tolerability of icatibant for treating HAE. An earlier completed Phase 3 trial examined subcutaneous icatibant specifically for acute HAE attacks, helping establish the evidence base behind its approval.

Reported Side Effects

Reports submitted to the FDA Adverse Event Reporting System (FAERS) reflect raw counts of submitted reports, not confirmed rates or proof of causation. The most frequently reported term is hereditary angioedema itself (3,685 reports), the condition being treated, followed by reports of drug ineffectiveness (846) and dose omission issues (695). Weight changes appear often in reports, with both decreased (655) and increased (622) weight noted, alongside product use issues (512), injection site pain (498), and off-label use (446).