hydroxyzine hydrochloride
hydroxyzine pamoate
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
☞ 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.