hydroxyzine hydrochloride

Apo-Hydroxyzine (CA), Atarax (CA) (UK), Novo-Hydroxyzin (CA), Nu-Hydroxyzine (CA), PMS-Hydroxyzine (CA), Riva-Hydroxyzine (CA), Ucerax (UK)

hydroxyzine pamoate

Vistaril

Pharmacologic class: Piperazine derivative

Therapeutic class: Anxiolytic, antihistamine, sedative-hypnotic

Pregnancy risk category NR

Action

Unknown. Anxiolytic and sedative effects may stem from suppression of activity in subcortical levels of CNS. Antihistamine effects may result from histamine suppression at cellular receptor sites.

Availability

Capsules: 25 mg, 50 mg, 100 mg (pamoate)

Injection: 25 mg/ml, 50 mg/ml

Oral suspension: 25 mg/5 ml (pamoate)

Syrup: 10 mg/5 ml

Tablets: 10 mg, 25 mg, 50 mg

Indications and dosages

➣ Psychiatric emergencies; acute or chronic alcoholism

Adults: 50 to 100 mg I.M. immediately, then q 4 to 6 hours p.r.n.

➣ Nausea and vomiting; adjunct in pre- and postoperative sedation

Adults: 25 to 100 mg I.M. q 4 to 6 hours

Children: 1.1 mg/kg I.M. q 4 to 6 hours

➣ Anxiety

Adults and children ages 6 and older: 50 to 100 mg P.O. q.i.d.

Children younger than age 6: 50 mg P.O. daily in divided doses

➣ Pruritus

Adults: 25 mg P.O. three or four times daily

Children ages 6 and older: 50 to 100 mg P.O. daily in divided doses

Children younger than age 6: 50 mg P.O. daily in divided doses

Off-label uses

• Seasonal allergic rhinitis

Contraindications

• Hypersensitivity to drug or cetirizine

• Early pregnancy

Precautions

Use cautiously in:

• severe hepatic dysfunction

• elderly patients.

Administration

See Don't administer I.V. or subcutaneously (may cause tissue necrosis).

• Use Z-track method for I.M. injection. Inject deep into large muscle (preferably, upper outer quadrant of buttock).

Adverse reactions

CNS: drowsiness, agitation, dizziness, headache, asthenia, ataxia

GI: nausea, constipation, dry mouth

GU: urinary retention

Respiratory: wheezing

Skin: flushing

Other: bitter taste, hypersensitivity reaction, pain or abscess at I.M. injection site

Interactions

Drug-drug. Anticholinergics, anti-depressants, antihistamines, phenothiazines, quinidine: additive effects of these drugs

Antidepressants, antihistamines, opioids, sedative-hypnotics, other CNS depressants: additive CNS depression

Drug-diagnostic tests. Skin tests using allergen extracts: false-negative results

Drug-herbs. Angel's trumpet, jimsonweed, scopolia: increased anticholinergic effects

Chamomile, hops, kava, skullcap, valerian: increased CNS depression

Drug-behaviors. Alcohol use: increased CNS depression

Patient monitoring

• Monitor closely for CNS depression and oversedation, especially if patient is receiving other CNS depressants.

• Assess for adverse effects, especially in elderly patients.

• Monitor liver function test results in patients with hepatic impairment.

Patient teaching

• Tell patient to contact prescriber if he experiences wheezing, muscle spasms, or incoordination.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Instruct patient to avoid alcohol while taking drug.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.