Can hydroxyzine (an antihistamine) be used to treat insomnia?

Hydroxyzine for Insomnia Treatment

Hydroxyzine is not recommended as a first-line treatment for insomnia due to its limited efficacy data, potential for daytime sedation, and risk of adverse effects, particularly in older adults. 1

Efficacy and Safety Concerns

• Hydroxyzine and other over-the-counter antihistamines are not recommended for the treatment of chronic insomnia due to lack of demonstrated efficacy and safety concerns 1
• The National Cancer Institute warns about the cautious use of antihistamines for sleep due to risks of daytime sedation and delirium, especially in older patients 1
• First-generation antihistamines like hydroxyzine are associated with significant sedative effects including drowsiness and performance impairment, even without subjective awareness of these effects 1

Adverse Effects

• Hydroxyzine can cause anticholinergic effects including dry mouth and eyes, constipation, urinary retention, and increased risk for narrow-angle glaucoma 1
• Older adults are particularly susceptible to psychomotor impairment from first-generation antihistamines, with increased risk of falls and subdural hematomas 1
• A comparative safety study found that sedating antihistamines had a 37% higher hazard ratio for suicide attempts compared to zolpidem, though this did not reach statistical significance 2
• There are case reports of adverse effects when hydroxyzine is combined with other medications, such as priapism when added to risperidone 3

Recommended Alternatives

• Cognitive Behavioral Therapy for Insomnia (CBT-I) is the recommended first-line treatment for chronic insomnia before considering pharmacological options 1, 4
• When pharmacotherapy is necessary, benzodiazepine receptor agonists (such as zolpidem) or ramelteon are recommended as first-line agents 1, 5
• For non-scheduled medication options, low-dose doxepin (3-6 mg) has better evidence for efficacy in sleep maintenance insomnia with minimal next-day effects 4, 6
• Sedating antidepressants such as trazodone, mirtazapine, and doxepin are preferred non-scheduled options over antihistamines, especially when comorbid depression/anxiety exists 4

Clinical Approach to Insomnia

1. Begin with CBT-I as the foundation of treatment 1, 4
2. If pharmacotherapy is needed:
   • First-line: Short/intermediate-acting benzodiazepine receptor agonists (zolpidem, eszopiclone) or ramelteon 1, 5
   • Second-line: Sedating antidepressants (doxepin, mirtazapine, trazodone) 4, 6
   • Avoid: Antihistamines like hydroxyzine, especially for chronic use 1

Important Considerations

• FDA labeling for hydroxyzine does not include insomnia as an approved indication; it is approved for anxiety, pruritus, and as a pre-anesthetic sedative 7
• The American Academy of Sleep Medicine explicitly does not recommend over-the-counter antihistamine sleeping aids due to lack of efficacy and safety data 1, 8
• If medication is prescribed for insomnia, it should be at the lowest effective dose for the shortest period possible 1, 9
• Regular follow-up is essential to assess efficacy, monitor for side effects, and evaluate the ongoing need for medication 1, 6

Special Populations

• In older adults, hydroxyzine and other first-generation antihistamines should be used with extreme caution due to increased sensitivity to adverse effects 1
• Patients with comorbid anxiety may occasionally benefit from hydroxyzine's anxiolytic properties, but evidence from Cochrane reviews indicates it cannot be recommended as a reliable first-line treatment even for anxiety 10