hydroxyzine (Vistaril)

Dosing and uses of Vistaril (hydroxyzine)

• Adult
• Pediatric
• Geriatric

 

Adult dosage forms and strengths

tablet

• 10mg
• 25mg
• 50mg

capsule

• 25mg
• 50mg
• 100mg

syrup/oral suspension

• 10mg/5mL

injectable solution

• 25mg/mL
• 50mg/mL

 

Anxiety

Symptomatic relief of anxiety associated with psychoneurosis and as adjunct in organic disease states

50-100 mg PO divided q6hr or 50-100 mg IM divided q4-6hr

Dosing considerations

• Continuation of therapy for >4 months has not been studied; reassess need for therapy periodically

 

Pruritus

Management of pruritus due to chronic urticaria, contact dermatoses, and histamine-mediated pruritus

25 mg PO/IM divided q6-8hr

 

Preoperative Sedation

50-100 mg PO or 25-100 mg Im

Dosing considerations

• If treatment is initiated IM, subsequent doses may be administered PO

 

Nausea & Vomiting (Off-label)

25-100 mg Im

 

Dosing Modifications

Renal Impairment

• >50 mL/min: Dose adjustment not necessary
• ≤50 mL/min: Administer 50% normal dose

Hepatic Impairment

• Change dosing interval to q24hr in patients with biliary cirrhosis

 

Pediatric dosage forms and strengths

tablet

• 10mg
• 25mg
• 50mg

capsule

• 25mg
• 50mg
• 100mg

syrup/oral susp

• 10mg/5mL

injectable solution

• 25mg/mL
• 50mg/mL

 

Anxiety

<6 years old: 50 mg/day PO divided q6hr

>6 years old: 50-100 mg/day PO divided q6hr

 

Pruritus

Management of pruritus due to chronic urticaria, contact dermatoses, and histamine-mediated pruritus

<6 years old: 50 mg/day PO divided q6hr

>6 years old: 50-100 mg/day PO divided q6hr

 

Preoperative Sedation

0.6 mg/kg PO

0.5-1.1 mg/kg Im

 

Geriatric dosage forms and strengths

 

Anxiety

Symptomatic relief of anxiety associated with psychoneurosis and as adjunct in organic disease states

50-100 mg PO divided q6hr or 50-100 mg IM divided q4-6hr

Continuation of therapy for >4 months has not been studied; reassess need for therapy periodically

 

Pruritus

25 mg PO/IM q6-8hr; increased to 25 mg q6-8hr

 

Nausea & Vomiting (Off-label)

25 mg Im

 

Dosing Modifications

Advanced age associated with reduced drug clearance and with greater risk of confusion, dry mouth, constipation, and other anticholinergic effects and toxicity; start at low end of dosage range, and observe closely

 

Vistaril (hydroxyzine) adverse (side) effects

Frequency not defined

Anticholinergic: Dry mouth

Central nervous system: Drowsiness (usually transitory and may disappear in a few days of continued therapy or upon reduction of the dose), involuntary motor activity (tremor, convulsions) usually with doses considerably higher than those recommended

Clinically significant respiratory depression has not been reported at recommended doses

 

Postmarketing Reports

Body as a whole: Allergic reaction

Nervous system: Headache

Psychiatric: Hallucination

Skin and appendages: Pruritus, rash, urticaria, fixed drug eruptions

 

Warnings

Contraindications

Documented hypersensitivity

SC, intra-arterial, or IV administration

 

Cautions

Nursing mothers

May cause CNS depression resulting in drowsiness; avoid driving or operating dangerous machinery

May cause oversedation and confusion in elderly patients; start on lower doses and monitor closely; avoid use

IM only for parenteral use; switch to PO ASAp

Use caution in patients with narrow-angle glaucoma, prostatic hyperplasia, or respiratory disease (asthma or COPD)

 

Pregnancy and lactation

Pregnancy category: Considered to be contraindicated in early (1st trimester) pregnancy until more human pregnancy data available; limited experience in human pregnancy, either for drug itself or drugs in same class or with similar mechanisms of action, including 1st trimester, current limited data suggests that the drug does not represent a significant risk of developmental toxicity including growth restriction, structural anomalies, functional/behavioral deficits, or death at any time in pregnancy

Lactation: Excretion in milk unknown; use with caution

 

Pregnancy categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

 

Pharmacology of Vistaril (hydroxyzine)

Mechanism of action

H1-receptor antagonist with low to moderate antihistaminic properties; inhibits respiratory, vascular, and GI smooth-muscle constriction

Moderate to high anticholinergic and antiemetic properties

 

Absorption

Onset: 15-30 min (PO)

Duration: Sedation, 4-6 hr; antipruritic, 1-12 hr; histamine-induced wheal and flare, 2-36 hr 

Peak serum time: 1-2 hr

 

Distribution

Vd: 16 L/kg (adults); 23 L/kg (elderly)

 

Metabolism

Metabolized by liver

 

Elimination

Half-life: 20 hr (adults); 29 hr (elderly); 37 hr (hepatic dysfunction)

Excretion: Urine

 

Administration

IM Incompatibilities

Additive: Aminophylline, amobarbital, chloramphenicol, ketorolac, penicillin G sodium/potassium, pentobarbital, phenobarbitaL

Syringe: Aminophylline, dimenhydrinate, haloperidol, heparin, ketorolac, penicillin, pentobarbital, phenytoin, ranitidine, vitamin B complex with C

 

IM Compatibilities

Additive (partial list): Cisplatin, cyclophosphamide, cytarabine, dimenhydrinate, etoposide, lidocaine, methotrexate, nafcillin

Syringe (partial list): Atropine, buprenorphine, cimetidine, diphenhydramine, fentanyl, glycopyrrolate, lidocaine, meperidine, midazolam, morphine, promethazine, scopolamine, sufentaniL