Hydroxyzine (Atarax) Dosage and Usage Guidelines
The recommended adult dosage of hydroxyzine (Atarax) is 10-50 mg 3-4 times daily, with adjustments needed for special populations including elderly patients, and those with hepatic or renal impairment. 1
Standard Dosing for Adults
- Anxiety/Sedation: 10-50 mg 3-4 times daily 1
- Nighttime sedation: 25-100 mg at bedtime 1
- Urticaria adjunct: 10-50 mg at night in addition to daytime non-sedating antihistamine 1
Special Population Considerations
Renal Impairment
- Moderate impairment: Reduce dose by 50% 1
- Severe impairment (creatinine clearance <10 mL/min): Avoid use 1
Hepatic Impairment
- Severe liver disease: Avoid use due to inappropriate sedating effects 1
Elderly Patients
- Starting dose: Begin at the lowest possible dose (typically 10 mg)
- Rationale: Elderly patients are more susceptible to confusion, over-sedation, and decreased renal/hepatic function 2
Pregnancy
- Contraindicated during early stages of pregnancy 1
- Alternative: If antihistamine therapy is necessary during pregnancy, chlorphenamine is often preferred due to its longer safety record 1
Important Safety Considerations
QT Prolongation Risk
- Caution in patients with:
- Pre-existing heart disease
- Electrolyte imbalances
- Concomitant use of other QT-prolonging medications
- Congenital long QT syndrome
- Recent myocardial infarction
- Uncompensated heart failure
- Bradyarrhythmias 2
Drug Interactions
- CNS depressants: Reduce dosage of concomitant narcotics, non-narcotic analgesics, and barbiturates due to potentiating effects 2
- QT-prolonging medications: Use caution with Class 1A or Class III antiarrhythmics, certain antipsychotics, antidepressants, and antibiotics 2
Common Side Effects
- Sedation/drowsiness: Most common side effect (28% vs 14% with placebo), typically transient 3
- Other common effects: Dry mouth, weight gain, loss of concentration 3
Clinical Pearls
- Sedation typically appears during the first week and progressively diminishes with continued use 3
- Hydroxyzine should not be used as monotherapy for chronic urticaria but may be beneficial when added to non-sedating antihistamines 1
- Patients should be warned about drowsiness and cautioned against driving or operating dangerous machinery 2
- Monitor for signs of Acute Generalized Exanthematous Pustulosis (AGEP), a rare but serious skin reaction 2
Monitoring
- Monitor for QT prolongation in high-risk patients
- Watch for excessive sedation, particularly in elderly patients
- Assess for improvement in target symptoms (anxiety, pruritus, etc.)
Hydroxyzine is effective for generalized anxiety disorder compared to placebo, with efficacy similar to benzodiazepines and buspirone, though sedation is more common 4.