Reactine , Zyrtec
Classifications: antihistamine; h1-receptor antagonist; non-sedating; Therapeutic: antihistamine, non-sedating; h1-receptor antagonist
Pregnancy Category: B
5 mg, 10 mg tablets; 5 mg, 10 mg chewable tablets; 5 mg/5 mL syrup
Cetirizine is a potent H1-receptor antagonist and thus an antihistamine without significant anticholinergic or CNS activity. Low lipophilicity combined
with its H1-receptor selectivity probably accounts for its relative lack of anticholinergic and sedative properties.
Effectively treats allergic rhinitis and chronic urticaria by eliminating or reducing the local and systemic effects of
Seasonal and perennial allergic rhinitis and chronic idiopathic urticaria.
Hypersensitivity to H1-receptor antihistamines or hydroxyzine; concurrent use of alcohol; hepatic or renal dysfunction; lactation, infants <6
Moderate to severe renal impairment, pregnancy (category B), children.
Route & Dosage
Adult: PO 510 mg once/d
Child: PO 25 y, 2.5 mg q.d. (max: 5 mg/d); ≥6 y, 510 mg q.d.
Adult: PO 10 mg q.d. or b.i.d.
- Consult physician about dosage if significant adverse effects appear. As elimination half-life is prolonged in the older
adult, dosage adjustments may be warranted.
Adverse Effects (≥1%)GI: Constipation
, diarrhea, dry mouth. CNS: Drowsiness, sedation, headache, depression
may decrease cetirizine clearance leading to toxicity.
Readily from GI tract. Peak:
1 h. Distribution:
93% protein bound; minimal CNS
Minimal (by CYP3A4). Elimination:
60% unchanged in urine within 24 h, 5% in feces. Half-Life:
Assessment & Drug Effects
- Monitor for drug interactions. As the drug is highly protein bound, the potential for interactions with other protein-bound
- Monitor for sedation, especially the older adult.
Patient & Family Education
- Do not use in combination with OTC antihistamines.
- Do not engage in driving or other hazardous activities, before experiencing your responses to the drug.