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Conestat alfa Side Effects

Medically reviewed by Last updated on May 4, 2024.

Applies to conestat alfa: intravenous solution reconstituted.

Serious side effects of Conestat alfa

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

Other side effects of Conestat alfa

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

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. Cerner Multum, Inc. "UK Summary of Product Characteristics."

2. (2015) "Product Information. Ruconest (conestat alfa)." Valeant Pharmaceuticals

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.