Home Drug Guide Cetirizine Hydrochloride

Drug Guide

Generic Name

Cetirizine Hydrochloride

Brand Names Zyrtec Allergy, Zyrtec Hives, Zyrtec, Children's Zyrtec Allergy, Children's Zyrtec Hives Relief, Children's Zyrtec Hives, Cetirizine Hydrochloride Allergy, Cetirizine Hydrochloride Hives Relief, Cetirizine Hydrochloride Hives, Children's Cetirizine Hydrochloride Allergy, Children's Cetirizine Hydrochloride Hives Relief, Zerviate, Quzyttir

Classification

Therapeutic: Antihistamine, Allergy Agent

Pharmacological: Piperazine Derivative H1 Receptor Antagonist

FDA Approved Indications

Allergic rhinitis (seasonal and perennial)
Chronic urticaria (hives)

Mechanism of Action

Cetirizine selectively antagonizes peripheral H1 receptors, thereby reducing the allergic response caused by histamine.

Dosage and Administration

Adult: 10 mg once daily, can be adjusted based on response and tolerability.

Pediatric: 2-6 years: 5 mg once daily; over 6 years: 10 mg once daily.

Geriatric: Start with lower dose in elderly; monitor for sedation and anticholinergic effects.

Renal Impairment: Dose adjustment needed; typically 5 mg or less in severe impairment.

Hepatic Impairment: Use with caution; no specific dose adjustment recommended, but monitor for adverse effects.

Pharmacokinetics

Absorption: Rapidly absorbed with peak plasma concentrations at ~1 hour.

Distribution: Widely distributed; crosses the blood-brain barrier minimally.

Metabolism: Minimal hepatic metabolism; primarily excreted unchanged.

Excretion: Urinary excretion of unchanged drug; also through feces.

Half Life: Approx. 8 hours (adults); longer in renal impairment.

Contraindications

Hypersensitivity to cetirizine or hydroxyzine.
Children under 2 years of age for some formulations.

Precautions

Use with caution in renal or hepatic impairment.
Monitor for sedation and anticholinergic effects.
Use caution in elderly due to increased sensitivity.

Adverse Reactions - Common

Drowsiness (Common)
Headache (Common)
Dry mouth (Less common)
Fatigue (Less common)

Adverse Reactions - Serious

Pruritus, rash, or other hypersensitivity reactions (Rare)
Cardiovascular reactions (e.g., tachycardia) (Rare)

Drug-Drug Interactions

Other central nervous system depressants (increased sedation)
Theophylline (may alter clearance)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for effectiveness and adverse effects, especially sedation.

Diagnoses:

Risk for sedation related to CNS effects.
Risk for allergic reaction if hypersensitive.

Implementation: Administer with or without food. Advise patient to avoid alcohol and CNS depressants.

Evaluation: Assess relief of allergy symptoms and adverse effects.

Patient/Family Teaching

Take medication as prescribed.
Avoid alcohol and sedatives while taking cetirizine.
Report any signs of allergic reactions or unusual side effects.

Special Considerations

Black Box Warnings:

No black box warnings for cetirizine.

Genetic Factors: Consider genetic variability in metabolism, though unlikely to impact typical dosing.

Lab Test Interference: No known significant interference with laboratory tests.

Overdose Management

Signs/Symptoms: Severe drowsiness, hallucinations, agitation, or seizures in overdose.

Treatment: Supportive care, activated charcoal if ingestion is recent, gastric lavage, and monitoring. No specific antidote.

Storage and Handling

Storage: At room temperature, away from moisture and light.

Stability: Stable under recommended storage conditions.