What is the use of hydroxyzine (antihistamine)?

From the Guidelines

Hydroxyzine should be used with caution due to its potential for sedation, performance impairment, and anticholinergic effects, and its use is generally not preferred over second-generation antihistamines for the treatment of allergic rhinitis. The medication works by blocking histamine H1 receptors in the body, which helps reduce allergic symptoms, and also affects certain brain chemicals that may be unbalanced in people with anxiety 1. The typical adult dosage ranges from 25-100 mg taken 3-4 times daily, while children receive lower doses based on weight. Common side effects include drowsiness, dry mouth, and dizziness. Hydroxyzine has been shown to result in clinically significant improvement compared to placebo in the treatment of interstitial cystitis/bladder pain syndrome, but its use is associated with common adverse effects such as short-term sedation and weakness 1.

Some key points to consider when using hydroxyzine include:

• The potential for sedation and performance impairment, which can be exacerbated by concomitant use of other CNS-active substances such as alcohol, sedatives, hypnotics, or antidepressant medication 1
• The risk of anticholinergic effects, including dryness of mouth and eyes, constipation, inhibition of micturition, and an increased risk for provocation of narrow angle glaucoma 1
• The need for caution when using hydroxyzine in elderly patients and those with certain medical conditions like glaucoma or urinary retention 1
• The importance of avoiding alcohol while taking hydroxyzine, as this can increase drowsiness 1
• The potential for cognitive decline, particularly in the elderly population, associated with the use of H1 blockers with anticholinergic effects 1

Overall, while hydroxyzine can be an effective treatment for certain conditions, its use should be carefully considered and monitored due to its potential for adverse effects. The most recent and highest quality study available suggests that hydroxyzine can be effective in the treatment of interstitial cystitis/bladder pain syndrome, but its use should be approached with caution 1.

From the FDA Drug Label

THE POTENTIATING ACTION OF HYDROXYZINE MUST BE CONSIDERED WHEN THE DRUG IS USED IN CONJUNCTION WITH CENTRAL NERVOUS SYSTEM DEPRESSANTS Since drowsiness may occur with use of this drug, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery while taking hydroxyzine.

The primary use of hydroxyzine is not explicitly stated in the provided drug labels. However, based on the information provided, it can be inferred that hydroxyzine has sedating and potentiating effects when used with other central nervous system depressants.

• It is used in conjunction with central nervous system depressants.
• It has a potentiating action when used with other drugs.
• Drowsiness may occur with its use, indicating a potential use for anxiety or insomnia. However, the exact use of hydroxyzine (e.g., for allergic reactions or anxiety) is not directly stated in the provided text 2.

From the Research

Uses of Hydroxyzine

• Hydroxyzine is an antihistamine medication used for the treatment of anxiety, particularly generalized anxiety disorder (GAD) 3, 4, 5.
• It has been shown to be effective in alleviating the acute symptoms of GAD, with some studies indicating that it is more effective than placebo 3, 5.
• Hydroxyzine has also been used to reduce stress and anxiety associated with coronary disease, and has been found to have a beneficial effect on sleep 4.

Efficacy and Acceptability

• Studies have found that hydroxyzine is equivalent in terms of efficacy, acceptability, and tolerability to other anxiolytic agents, such as benzodiazepines and buspirone 3.
• However, hydroxyzine has been associated with a higher rate of sleepiness/drowsiness compared to other active comparators 3.
• The use of hydroxyzine has also been found to be acceptable and tolerable, with a low risk of adverse effects, although it can cause side effects such as dry mouth, weight gain, and loss of concentration 5.

Clinical Trials

• Recent clinical trials have confirmed the efficacy of hydroxyzine in the treatment of GAD, with one study finding that it demonstrated greater and more rapid cognitive improvement compared to lorazepam 4.
• Another study found that the addition of hydroxyzine to morphine in the prehospital setting did not reduce pain or anxiety in patients with acute severe pain, and therefore is not indicated based on those results 6.
• A study on the value of hydroxyzine in GAD found that it produced a statistically and clinically significant anxiolytic effect, commencing during the first week of treatment and maintained throughout the 4-week period and after abrupt discontinuation without rebound of anxiety or withdrawal symptoms 5.

Dosing and Administration

• Bedtime dosing of hydroxyzine has been investigated as a dosing strategy to minimize reaction time degradation and adverse subjective symptoms, and has been found to maintain skin H1-receptor antagonism the following morning and alleviate the prolongation of reaction times previously reported with hydroxyzine in divided doses 7.