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Cetirizine

ZYRTEC

What it isSecond-generation H1 antagonist; allergic rhinitis and urticaria.

Why it mattersAmong OTC second-generation agents, it is especially effective for urticaria but more likely to cause drowsiness.

What it changesReduce in renal impairment and warn about driving until sedation is known; alcohol and other sedatives add impairment.

FDA-approved for

FDA label

FDA dosingPopulationStartTargetMax
Allergy symptomsAdult & children >=6 yr10 mg QD10 mg QD (5 mg may suffice for milder symptoms)10 mg/24h

Renal Undefined

Hepatic Undefined

Instructions

Pregnancy Undefined

Lactation Undefined

NO BOXED WARNINGS

Principal riskSedation, more than loratadine

Cost, est. cash$10–$400/month

Generic entry2007

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4
Overdose danger1 / 4
Weight-gain liability1 / 4
Sedation liability1 / 4
QT / Torsades0 / 4
Direct muscarinic antagonism0 / 4
Embryofetal risk0 / 4

Legacy pregnancy categoryB

Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.

Mechanism of action: Cetirizine ballicule

Cetirizine ballicule: receptor binding, kinetics and half-life diagram

Open Cetirizine in the interactive console ↗

Memory aids: mascots and interaction avatars

Cetirizine ZYRTEC mascot mnemonic cartoon
“Sir Tech, the Sitter”
Crown → antihistamine
Cetirizine Box: minimal PK interactions avatar
Box: minimal PK interactions

Open Cetirizine in the interactive console ↗