Hydroxyzine
Class: First-generation antihistamine (H1 receptor antagonist) with sedative, anxiolytic, and antiemetic properties
Indications
- Pruritus due to allergic conditions (eczema, urticaria)
- Allergic rhinitis
- Anxiety or tension states (preoperative or adjunct therapy)
- Nausea and vomiting (off-label use)
- Sleep aid in short-term insomnia (secondary use)
Dosage
- Adults: 25–100 mg/day divided into 3–4 doses, or 50–100 mg once at bedtime for sedation
- Children 6–12 years: 50–100 mg/day divided into 2–3 doses
- Children 2–6 years: 2–4 mg/kg/day divided doses
- Max dose: 400 mg/day (rarely used)
Major Side Effects
- Marked drowsiness, sedation
- Dizziness, headache
- Dry mouth, blurred vision
- Confusion (especially elderly)
- QT prolongation at high doses
Contraindications
- Hypersensitivity to hydroxyzine or cetirizine/levocetirizine (metabolite)
- Early pregnancy (especially first trimester, unless necessary)
- Patients with prolonged QT interval or severe cardiac disease
Compatible Solvent / Form
- Oral tablets (10 mg, 25 mg, 50 mg, 100 mg)
- Oral syrup (10 mg/5 mL, 25 mg/5 mL)
- Injectable (intramuscular, intravenous – hospital use)
Special Precautions
- Highly sedating; avoid driving or operating machinery
- Caution in elderly, infants, and patients with respiratory disease
- Can potentiate CNS depressants including alcohol, benzodiazepines
- Pregnancy Category C – use only if clearly indicated
Key Point: Hydroxyzine is a potent first-generation antihistamine with additional sedative and anxiolytic effects, primarily used for pruritus, anxiety, and preoperative sedation.