HYDROXYZINE HYDROCHLORIDE

(hye-drox'i-zeen)

Atarax Syrup, Hyzine-50, Vistaril Intramuscular, Vistacon, Vistaject-25 & -50
HYDROXYZINE PAMOATE
Vistaril Oral
Classifications: antihistamine; h₁-receptor antagonist; antipruritic;
Therapeutic: antihistamine; antipruritic; antianxiety; antiemetic
Pregnancy Category: C

Availability

Hydroxyzine HCl: 10 mg, 25 mg, 50 mg tablets; 10 mg/5 mL syrup; 25 mg/5 mL oral suspension; 25 mg/mL, 50 mg/mL injection

Hydroxyzine Pamoate: 25 mg, 50 mg, 100 mg capsules; 25 mg/5 ml suspension

Action

H₁-receptor antagonist; effective in treatment of histamine-mediated pruritus or other allergic reactions. Its tranquilizing effect is produced primarily by depression of hypothalamus and brain-stem reticular formation, rather than cortical areas.

Therapeutic Effect

Effective as an antianxiety agent and sedative. Additionally, it is an effective agent for pruritus.

Uses

Emotional or psychoneurotic states characterized by anxiety, tension, or psychomotor agitation; to relieve anxiety, control nausea and emesis, and reduce narcotic requirements before or after surgery or delivery. Also used in management of pruritus due to allergic conditions (e.g., chronic urticaria), atopic and contact dermatoses, and in treatment of acute and chronic alcoholism with withdrawal symptoms or delirium tremens.

Contraindications

Known hypersensitivity to hydroxyzine; use as sole treatment in psychoses or depression; pregnancy (category C); lactation.

Cautious Use

History of allergies; GI disorders; cardiac disease; COPD; older adults.

Route & Dosage

Anxiety
Adult: PO 25–100 mg t.i.d. or q.i.d. IM 25–100 mg q4–6h
Child: PO <6 y, 50 mg/d in divided doses; >6 y, 50 mg/d in divided doses IM 1.1 mg/kg q4–6h

Pruritus
Adult: PO 25 mg t.i.d. or q.i.d. IM 25 mg q4–6h
Geriatric: PO 10 mg 3–4 times daily
Child: PO >6 y, 50–100 mg/d in divided doses; <6 y, 50 mg/d in divided doses IM 1.1 mg/kg q4–6h

Nausea
Adult: IM 25–100 mg q4–6h
Child: IM 1.1 mg/kg q4–6h

Administration

Oral

Note: Tablets may be crushed and taken with fluid of patient's choice. Capsule may be emptied and contents swallowed with water or mixed with food. Liquid formulations are available.

Intramuscular

Give deep into body of a relatively large muscle. The Z-track technique of injection is recommended to prevent SC infiltration.
Recommended site: In adult, the gluteus maximus or vastus lateralis; in children, the vastus lateralis.
Protect all forms from light. Store at 15°–30° C (59°–86° F) unless otherwise specified.

INCOMPATIBILITIES Solution/additive: Aminophylline, amobarbital, chloramphenicol, dimenhydrinate, penicillin G, pentobarbital, phenobarbital.

Adverse Effects (≥1%)

CNS: Drowsiness (usually transitory), sedation, dizziness, headache. CV: Hypotension. GI: Dry mouth. Body as a Whole: Urticaria, dyspnea, chest tightness, wheezing, involuntary motor activity (rare). Hematologic: Phlebitis, hemolysis, thrombosis. Skin: Erythematous macular eruptions, erythema multiforme, digital gangrene from inadvertent IV or intraarterial injection, injection site reactions.

Diagnostic Test Interference

Possibility of false-positive urinary 17-hydroxycorticosteroid determinations (modified Glenn-Nelson technique).

Interactions

Drug: Alcohol and cns depressants add to cns depression; tricyclic antidepressants and other anticholinergics have additive anticholinergic effects; may inhibit pressor effects of epinephrine.

Pharmacokinetics

Absorption: Readily from GI tract. Onset: 15–30 min PO. Duration: 4–6 h. Distribution: Not known if it crosses placenta or is distributed into breast milk. Metabolism: In liver. Elimination: In bile.

Nursing Implications

Assessment & Drug Effects

Evaluate alertness. Drowsiness may occur and usually disappears with continued therapy or following reduction of dosage.
Monitor condition of oral membranes daily when patient is on high dosage of hydroxyzine.
Reevaluate usefulness of drug periodically.
Reduce dosage of the depressant up to 50% when CNS depressants are prescribed concomitantly.

Patient & Family Education

Do not drive or engage in other potentially hazardous activities until response to drug is known.
Do NOT take alcohol and hydroxyzine at the same time.
Notify physician immediately if you become pregnant.
Relieve dry mouth by frequent warm water rinses, increasing fluid intake, and use of a salivary substitute (e.g., Moi-Stir, Xero-Lube).
Give teeth scrupulous care. Avoid irritation or abrasion of gums and other oral tissues.
Consult physician before self-dosing with OTC medications.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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