Home Drug Guide Hydroxyzine Pamoate

Drug Guide

Generic Name

Hydroxyzine Pamoate

Brand Names Vistaril, Hy-pam 25

Classification

Therapeutic: Antihistamine, Anti-anxiety agent

Pharmacological: First-generation H1 antihistamine, Sedative

FDA Approved Indications

Anxiety and tension in adults
Preoperative medication to sedate
Treatment of pruritus due to allergies

Mechanism of Action

Hydroxyzine is an H1 antihistamine that blocks histamine receptors, reducing allergic responses and producing sedative effects through CNS depression.

Dosage and Administration

Adult: 25-100 mg up to four times daily as needed, tailored to patient response.

Pediatric: Typically 0.5 mg/kg per dose, not to exceed 25 mg per dose. Adjust based on age and weight.

Geriatric: Start at lower doses to minimize sedation and anticholinergic effects.

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

Hepatic Impairment: Use with caution; monitor for increased sedative effects.

Pharmacokinetics

Absorption: Rapidly absorbed after oral administration.

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

Metabolism: Minimal hepatic metabolism; primarily excreted unchanged.

Excretion: Renal excretion; dose adjustment needed in renal impairment.

Half Life: Approximately 20-40 hours.

Contraindications

Hypersensitivity to hydroxyzine or piperazine derivatives
Early pregnancy (category C), unless benefits outweigh risks.

Precautions

Use with caution in elderly due to increased risk of sedation and falls.
Warn about risk of respiratory depression in susceptible individuals.
May impair ability to operate machinery or drive.

Adverse Reactions - Common

Sedation (Common)
Dizziness (Common)
Dry mouth (Common)
Blurred vision (Uncommon)

Adverse Reactions - Serious

Respiratory depression (Rare)
Allergic reactions, including rash or anaphylaxis (Rare)

Drug-Drug Interactions

CNS depressants (e.g., alcohol, sedatives, tranquilizers)
Other anticholinergic drugs (e.g., atropine, TCAs)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for sedation, respiratory status, and anticholinergic effects.

Diagnoses:

Risk for falls related to sedation
Impaired urinary elimination due to anticholinergic effects

Implementation: Administer with food if GI upset occurs. Use lowest effective dose.

Evaluation: Assess level of sedation and effectiveness of anxiety or pruritus control.

Patient/Family Teaching

Avoid alcohol and CNS depressants.
Caution when driving or operating machinery.
Report excessive drowsiness or allergic reactions.
Do not stop medication abruptly.

Special Considerations

Black Box Warnings:

Sedation can impair ability to perform tasks requiring alertness.
Use with caution in patients with pre-existing QT prolongation or those on QTc prolonging drugs.

Genetic Factors: None specified.

Lab Test Interference: May cause false-positive results in certain allergy skin tests.

Overdose Management

Signs/Symptoms: Extreme drowsiness, hallucinations, dry mouth, mydriasis, tachycardia, seizures in severe cases.

Treatment: Supportive care; activated charcoal if within 1 hour of ingestion; manage airway, breathing, circulation. Hemodialysis is not typically used.

Storage and Handling

Storage: Store at room temperature; protect from light and moisture.

Stability: Stable under recommended conditions for shelf life.