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Cetirizine (Zyrtec)

Organon and Co · FDA-approved active Small molecule

Cetirizine is a selective H1-receptor antagonist that blocks histamine binding to H1 receptors on cells, preventing allergic symptoms.

Cetirizine is a selective H1-receptor antagonist that blocks histamine binding to H1 receptors on cells, preventing allergic symptoms. Used for Allergic rhinitis (seasonal and perennial), Chronic urticaria, Allergic conjunctivitis.

At a glance

Generic nameCetirizine (Zyrtec)
Also known asZyrtec®, Zyrtec
SponsorOrganon and Co
Drug classH1-receptor antagonist (second-generation antihistamine)
TargetH1 receptor
ModalitySmall molecule
Therapeutic areaImmunology / Allergy
PhaseFDA-approved

Mechanism of action

Cetirizine competitively inhibits histamine at H1 receptors, which are responsible for allergic responses including itching, sneezing, and urticaria. As a second-generation antihistamine, it is highly selective for H1 receptors and has minimal central nervous system penetration due to its hydrophilic nature and poor blood-brain barrier crossing, resulting in reduced sedation compared to first-generation antihistamines.

Approved indications

Common side effects

Key clinical trials

Primary sources

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SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results

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