Home Drug Guide Hydroxyzine Hydrochloride

Drug Guide

Generic Name

Hydroxyzine Hydrochloride

Brand Names Atarax, Vistaril, Hydroxyzine, Orgatrax

Classification

Therapeutic: Antihistamine, anxiolytic, sedative

Pharmacological: First-generation H1 receptor antagonist

FDA Approved Indications

Anxiety and tension
Preoperative sedation
Nausea and vomiting
Itching (urticaria)

Mechanism of Action

Hydroxyzine selectively antagonizes H1 histamine receptors, reducing allergic responses and exerting sedative and anxiolytic effects.

Dosage and Administration

Adult: Typically 25-100 mg taken orally 3-4 times daily, titrated based on response and tolerability.

Pediatric: Dosing varies based on age and weight; generally, 0.5-1 mg/kg per dose, up to 50 mg per dose, administered 3-4 times daily.

Geriatric: Start at lower doses due to increased sensitivity and risk of sedation; e.g., 25 mg once daily, titrating as needed.

Renal Impairment: Use with caution; dose adjustments may be necessary.

Hepatic Impairment: Use with caution; monitor for increased sedation and adverse effects.

Pharmacokinetics

Absorption: Well absorbed orally with peak plasma levels in 2 hours.

Distribution: Widely distributed in body tissues, crosses the blood-brain barrier.

Metabolism: Metabolized in the liver, primarily via CYP3A4 sources.

Excretion: Excreted mainly in urine as unchanged drug and metabolites.

Half Life: Approximately 20-25 hours.

Contraindications

Intolerance to hydroxyzine or similar drugs
Newborns or premature infants
Patients taking large amounts of CNS depressants

Precautions

Use with caution in elderly due to risk of sedation and confusion.
Pregnancy category C; use only if clearly needed. Lactation: Caution advised; consider potential effects on nursing infant.

Adverse Reactions - Common

Drowsiness or sedation (Common)
Dry mouth (Common)
Fatigue (Common)

Adverse Reactions - Serious

Respiratory depression (rare) (Serious)
QT prolongation and cardiac arrhythmias (rare) (Serious)
Seizures (rare) (Serious)

Drug-Drug Interactions

CNS depressants (additive sedation)
Erythromycin and ketoconazole (may inhibit metabolism)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor sedation level, for signs of hypersensitivity, and hepatic function as appropriate.

Diagnoses:

Risk for injury related to sedation
Impaired oral mucous membranes related to dry mouth

Implementation: Administer with food or water to reduce gastrointestinal upset; avoid activities requiring alertness until response is known.

Evaluation: Assess relief of symptoms, monitor for adverse effects, and evaluate patient safety.

Patient/Family Teaching

Advise patient to avoid alcohol and CNS depressants.
Inform about potential for drowsiness and to avoid driving or operating machinery.
Instruct to report worsening symptoms or adverse effects.

Special Considerations

Black Box Warnings:

None

Genetic Factors: No specific genetic factors identified influencing response.

Lab Test Interference: May alter some allergy testing results.

Overdose Management

Signs/Symptoms: Severe drowsiness, dry mouth, flushing, hallucinations, seizures, and possibly respiratory depression.

Treatment: Supportive care, activated charcoal if ingestion was recent, and symptomatic management. In cases of severe overdose, consider airway management, IV fluids, and monitoring cardiac rhythm.

Storage and Handling

Storage: Store at room temperature away from moisture, light, and children.

Stability: Stable under recommended storage conditions.