Recombinant C1 esterase inhibitor Pregnancy: Not recommended for use during pregnancy or breast-feeding unless the treating physician judges the benefits to outweigh the possible risks. There is no experience in pregnant and breast-feeding women; reproductive toxicity was observed in one animal study.

Conestat alfa

Brand names: Ruconest

Conestat alfa is a recombinant human C1-esterase inhibitor used to treat acute angioedema attacks in adults and adolescents with hereditary angioedema due to C1-esterase inhibitor deficiency.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Body weight up to 84 kg: one intravenous injection of 50 U/kg body weight. Body weight of 84 kg or greater: one intravenous injection of 4200 U (2 vials).

Route: Intravenous - the required volume of reconstituted solution given as a slow intravenous injection over approximately 5 minutes

Frequency: Single dose for an acute hereditary angioedema attack; in case of insufficient clinical response an additional dose (50 U/kg body weight up to 4200 U) can be administered - in adults and adolescents if not responded adequately after 120 minutes

Max: 4200 U per dose (2 vials); not more than two doses should be administered within 24 hours

Ruconest should be initiated under the guidance and supervision of a physician experienced in the diagnosis and treatment of hereditary angioedema. In the majority of cases a single dose is sufficient to treat an acute angioedema attack. For patients up to 84 kg the volume to administer is calculated from body weight; for patients of 84 kg or above the volume required is 28 ml (4200 U, 2 vials). Elderly (>=65 years): data are limited; no rationale for a different response. Hepatic impairment: no clinical experience; no recommendation on dose adjustment can be made. Must be administered by a healthcare professional until the patient or caregiver is competent to self-administer after proper training.

Paediatric dose

Dose: 50 U/kg (units per kg body weight - NOT mg)/kg

Route: Intravenous injection over approximately 5 minutes

Frequency: Single dose per acute attack; an additional dose may be administered if the child has not responded adequately after 60 minutes

Max: 4200 U (2 vials) for body weight of 84 kg or greater; not more than two doses within 24 hours

SPC section 4.2: 'Ruconest may be used in paediatric patients (2 years and older) at the same dose as in adults (50 U/kg body weight).' The safety and efficacy of Ruconest in children less than 2 years old have not been established and no clinical data are available. Verify against a children's formulary before administration.

Dose adjustments

Renal

No dose adjustment is necessary in patients with renal impairment, since conestat alfa does not undergo renal clearance.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Known or suspected allergy to rabbits (conestat alfa is derived from the milk of transgenic rabbits and contains traces of rabbit protein)
Hypersensitivity to the active substance or to any of the excipients

Side effects

Nausea (common)
Headache, dizziness, vertigo, hypoaesthesia (uncommon)
Diarrhoea, abdominal discomfort, oral paraesthesia (uncommon)
Urticaria, throat irritation, auricular swelling (uncommon)
Anaphylaxis (uncommon); hypersensitivity reactions (frequency not known)

Interactions

No interaction studies have been performed
Tissue-type plasminogen activator (tPA) - scientific literature indicates an interaction with C1-INH containing medicinal products; Ruconest should not be administered simultaneously with tPA

Clinical monograph

How it works

It is a recombinant form of human C1-esterase inhibitor that replaces the deficient or dysfunctional protein, restoring regulation of the complement and contact (kallikrein-kinin) systems and reducing bradykinin-mediated swelling.

Prescribing in practice

It is produced in the milk of transgenic rabbits and is contraindicated in patients with known or suspected allergy to rabbits or rabbit-derived products.
It is administered by slow intravenous injection for the treatment of acute attacks.
Hypersensitivity reactions can occur and may be difficult to distinguish from angioedema, so it should be given where appropriate management is available, per the SPC.

Monitoring

Monitor for resolution of the acute attack and for signs of hypersensitivity during and after administration.

Counselling the patient

This medicine treats sudden swelling attacks of hereditary angioedema.
Tell your clinician if you are allergic to rabbits, as it is derived from rabbit milk.
Seek urgent help if you develop signs of an allergic reaction such as rash, wheeze or worsening swelling.

Evidence & guidelines

Conestat alfa is supported by randomised controlled trials demonstrating reduced time to relief of acute hereditary angioedema attacks.

Reference: Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

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