What are the uses of hydroxyzine (antihistamine) prescription?

Uses of Hydroxyzine Prescription

Hydroxyzine is a first-generation antihistamine with multiple clinical applications including treatment of anxiety, pruritus (itching), sedation for sleep, and as an adjunct for managing nausea, though its use should be carefully considered due to significant sedative effects and potential safety concerns.

Primary Clinical Indications

Anxiety Management

• Hydroxyzine can be used for treatment of generalized anxiety disorder (GAD), though it is not typically considered a first-line treatment due to limited high-quality evidence 1
• It has shown greater efficacy than placebo for anxiety symptoms, with effectiveness comparable to benzodiazepines and buspirone 1
• Dosing for anxiety typically ranges from 10-50 mg, with higher doses potentially causing more significant sedation 2

Pruritus (Itching) Treatment

• Effective for managing pruritus associated with allergic conditions, urticaria (hives), and dermatological reactions 2
• Can be used as a sedating antihistamine at night (10-50 mg) in combination with a non-sedating antihistamine during the day for patients with urticaria who have sleep disturbances 2
• May be particularly useful for pruritus associated with anticancer therapies, especially when nighttime itching disrupts sleep 2

Sleep Aid

• Used off-label for insomnia due to its sedative properties 3
• Limited evidence suggests potential efficacy for sleep onset and maintenance issues in doses ranging from 25-100 mg at bedtime 3
• May be considered as a short-term treatment option for adults with insomnia when other therapies have been ineffective or contraindicated 3

Management of Nausea and Chemical Restraint

• Can be used as an adjunctive treatment for opioid-induced pruritus and nausea 2
• Employed in acute psychiatric settings for chemical restraint in agitated patients, particularly in children and adolescents 2

Important Safety Considerations

Sedation and Performance Impairment

• Significant sedative effects can impair driving ability, work performance, and cognitive function 2, 4
• Associated with increased risk of motor vehicle accidents - drivers in fatal accidents were 1.5 times more likely to be taking first-generation antihistamines 2
• Performance impairment can occur without subjective awareness of drowsiness 2
• Impaired driving performance with hydroxyzine worsens with concurrent activities like cell phone use 2

Cardiovascular Concerns

• Cases of QT prolongation and Torsade de Pointes have been reported during post-marketing surveillance 5
• Should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, recent myocardial infarction, heart failure, or bradyarrhythmias 5
• Caution is recommended when used with other medications known to prolong the QT interval 5

Special Populations

• Pregnancy: Contraindicated during early pregnancy according to UK manufacturer's guidelines 2
• Renal impairment: Dose should be halved in moderate renal impairment; avoid in severe renal impairment 2
• Hepatic impairment: Should be avoided in severe liver disease due to inappropriate sedating effects 2
• Elderly patients: Start with lower doses and monitor closely; elderly patients are more sensitive to psychomotor impairment and at increased risk for falls and anticholinergic effects 2, 5

Drug Interactions

• Has potentiating action when used with other CNS depressants (narcotics, non-narcotic analgesics, barbiturates) - dosage of these medications should be reduced 5
• Concomitant use with alcohol, sedatives, hypnotics, or antidepressants may further enhance performance impairment 2
• When combined with certain antipsychotics like risperidone, may increase risk of rare side effects such as priapism due to additive alpha-adrenergic antagonism 6

Dosing Considerations

• Anxiety: 10-50 mg per dose 2
• Pruritus/urticaria: 10-50 mg, often given at night 2
• Insomnia: 25-100 mg at bedtime (off-label) 3
• Dose should be reduced in elderly patients and those with moderate renal impairment 2, 5

Clinical Pearls and Pitfalls

• Second-generation antihistamines are generally preferred over hydroxyzine for daytime use due to their reduced sedative effects 2
• The AM/PM dosing regimen (second-generation antihistamine in morning, hydroxyzine at night) may still result in daytime drowsiness due to hydroxyzine's prolonged half-life 2
• Patients should be warned about drowsiness and cautioned against driving or operating dangerous machinery while taking hydroxyzine 5
• May rarely cause acute generalized exanthematous pustulosis (AGEP), a serious skin reaction requiring discontinuation 5
• Cross-sensitivity may exist with cetirizine or levocetirizine in patients who have experienced hypersensitivity reactions to hydroxyzine 5