What are the side effects of Vistaril (hydroxyzine)?

Side Effects of Vistaril (Hydroxyzine)

Hydroxyzine causes significant drowsiness and cognitive impairment that persists longer than patients realize, with drivers taking this medication being 1.5 times more likely to be responsible for fatal automobile accidents compared to non-users. 1

Central Nervous System Effects

The most prominent and dangerous side effects involve CNS depression:

• Drowsiness and sedation are the most common side effects, though they are usually transitory and may diminish with continued therapy or dose reduction 2
• Performance impairment occurs without subjective awareness, meaning patients feel alert while experiencing significant cognitive deficits 1
• Impairment persists longer than plasma drug levels due to prolonged half-lives of hydroxyzine and its active metabolites 1, 3
• Even bedtime-only dosing causes significant daytime drowsiness, decreased alertness, and performance impairment the following day 1, 3
• Impaired driving performance worsens significantly with concurrent cell phone use 1
• Workers experience reduced productivity and increased occupational accident risk 1, 3
• Children may experience impaired learning and school performance 1, 3
• Paradoxical CNS stimulation may occur, particularly in children 1
• Headache has been reported in post-marketing surveillance 2
• Rare instances of tremor and convulsions have been reported, usually with doses considerably higher than recommended 2
• Hallucinations have been reported in post-marketing experience 2

Anticholinergic Effects

Hydroxyzine produces typical anticholinergic side effects:

• Dry mouth is commonly reported 2
• Dry eyes 1
• Constipation 1, 3
• Inhibition of micturition (urinary retention) 1, 3
• Increased risk for provocation of narrow-angle glaucoma 1, 3
• Blurred vision 4

Cardiac Effects

QT prolongation and Torsade de Pointes have been reported in post-marketing experience 2. Hydroxyzine may produce abnormal ventricular repolarization when given in substantial doses or to susceptible individuals, and this effect may be augmented by concurrent use of phenothiazines, tricyclic antidepressants, antiparkinson drugs, atropine, quinidine, or procainamide 5.

Dermatologic Reactions

• Acute Generalized Exanthematous Pustulosis (AGEP) has been associated with oral hydroxyzine 2
• Fixed drug eruptions 2
• Pruritus, rash, and urticaria have been reported 2

Special Population Risks

Elderly Patients

• Older adults are more sensitive to psychomotor impairment from hydroxyzine 1, 6, 3
• Increased risk for falls, fractures, and anticholinergic complications 1, 6, 3
• Sedating antihistamines like hydroxyzine should not be prescribed for pruritus in elderly patients due to these heightened risks 6

Pregnancy and Neonatal Effects

• Hydroxyzine is contraindicated during early pregnancy 1, 6, 3
• Neonatal withdrawal syndrome can occur with maternal use, including tremors, irritability, hyperactivity, jitteriness, shrill cry, myoclonic jerks, hypotonia, increased respiratory and heart rates, feeding problems, and clonic movements 1, 3
• Withdrawal symptoms in neonates may persist up to 5 weeks even with treatment 1, 3

Renal and Hepatic Impairment

• Dose should be halved in moderate renal impairment and avoided in severe renal impairment 1, 6, 3
• Should be avoided in severe liver disease due to inappropriate sedating effects 1, 6, 3

Drug Interactions

Concomitant use with other CNS-active substances (alcohol, sedatives, hypnotics, antidepressants, benzodiazepines) further enhances performance impairment and creates compounding cognitive deficits 1, 3. Co-administration with other anxiolytic agents like benzodiazepines is contraindicated due to heightened risk of additive CNS depression 6.

Common Pitfalls

The most critical pitfall is underestimating the duration and severity of cognitive impairment. Patients often feel they have recovered when objective impairment persists, creating a false sense of safety for activities like driving 1, 3. The medication should be used short-term only for symptom management 3, and patients must be explicitly warned about driving risks even when they feel alert 1, 6.