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Conestat alfa Side Effects

For the Consumer

Applies to conestat alfa: intravenous powder for injection

Get emergency medical help if you have signs of an allergic reaction: rash or hives; chest tightness, wheezing, difficult breathing; blue-colored lips or gums; fast heartbeats; feeling like you might pass out; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • sudden numbness or weakness (especially on one side of the body);

  • sudden severe headache, slurred speech, problems with vision or balance; or

  • pain, swelling, warmth, or redness in one or both legs.

Common side effects may include:

  • headache;

  • diarrhea; or

  • nausea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to conestat alfa: intravenous powder for injection


The most common adverse reactions were headache, nausea, and diarrhea.[Ref]

Nervous system

Very common (10% or more): Headache (up to 10%)
Common (1% to 10%): Vertigo, procedural headache
Uncommon (0.1% to 1%): Paresthesia[Ref]


Common (1% to 10%): Angioedema, erythema marginatum, skin burning sensation
Uncommon (0.1% to 1%): Urticaria
Postmarketing reports: Rash[Ref]


Common (1% to 10%): Nausea, diarrhea
Uncommon (0.1% to 1%): Abdominal discomfort, oral paresthesia
Postmarketing reports: Abdominal pain[Ref]


Common (1% to 10%): Sneezing
Uncommon (0.1% to 1%): Throat irritation[Ref]


Common (1% to 10%): Fibrin D-dimer increased[Ref]


Common (1% to 10%): C-reactive protein increased[Ref]


Common (1% to 10%): Back pain[Ref]


Common (1% to 10%): Lipoma


Uncommon (0.1% to 1%): Swelling[Ref]


1. "Product Information. Ruconest (conestat alfa)." Valeant Pharmaceuticals, Costa Mesa, CA.

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Not all side effects for conestat alfa may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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