Other Names/Brands

Bestalin, Vistaril, Atarax

Mechanism of Action

Hydroxyzine works as an antihistamine, blocking the action of histamine, a chemical in the body that causes allergic reactions such as itching, rashes, and sneezing. Hydroxyzine also has a sedative effect because it affects the central nervous system, making it often used to treat anxiety and nausea and promote sleep. This medication works by blocking H1 receptors in the brain and body, which reduces allergic responses and provides a calming effect.

Indications

Hydroxyzine is indicated for the treatment of various conditions, including allergic reactions such as urticaria (hives) and dermatitis, due to its ability to relieve itching and inflammation. Furthermore, hydroxyzine is used as an adjunct therapy for short-term anxiety management, as a sedative before surgical procedures, and to reduce nausea and vomiting. It is also used in the management of mild sleep disorders due to its sedative effects.

Contraindications

Hydroxyzine is contraindicated in patients with hypersensitivity to hydroxyzine or any other component of this medication, as well as in patients allergic to other piperazine antihistamines such as cetirizine and levocetirizine.

This medication should also not be used in patients with QT interval prolongation or certain heart rhythm disorders due to the risk of serious arrhythmias. Furthermore, hydroxyzine is contraindicated in pregnant women, especially during the first trimester, as it may affect fetal development.

Side Effects

Common side effects of hydroxyzine include drowsiness, dizziness, dry mouth, and headache, due to its effects on the central nervous system. Some patients may also experience gastrointestinal disturbances such as nausea or constipation.

Less common but serious side effects include severe allergic reactions, heart rhythm disturbances (such as QT prolongation), and impaired coordination. Due to its sedative effects, hydroxyzine may impair the ability to drive or operate machinery, so it should be used with caution, especially in the elderly or in patients with impaired liver or kidney function.

Preparations

Hydroxyzine is available in various forms, including tablets, capsules, syrup, and injections. Tablets and capsules are typically used to treat allergies, anxiety, or sleep disorders, while syrups are often prescribed to children or patients with difficulty swallowing.

Injectable forms are used in hospital settings to provide a sedative effect or treat more serious allergic reactions. This form allows for flexible administration of the medication according to the patient's needs and condition.

Dosage

Hydroxyzine dosage varies depending on the patient's age and the indication for treatment. For adults, the typical dose for anxiety or allergies is 25 to 100 mg per day, divided into several doses. In children, the dose is adjusted based on weight and age, usually lower than the adult dose. Hydroxyzine can also be given as a single dose before medical procedures for a sedative effect.

Safety of Drugs

Hydroxyzine is classified as a pregnancy category C by the FDA, meaning that animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in humans. Therefore, hydroxyzine should only be used during pregnancy if the expected benefit outweighs the potential risk to the fetus.

Caution should also be exercised when using this medication during breastfeeding, as it can pass into breast milk and affect the infant. Consult your doctor before using hydroxyzine during pregnancy or breastfeeding.

Drug Interactions

Hydroxyzine can interact with several other medications that affect the central nervous system, such as tranquilizers, antidepressants, and sleeping pills, increasing the effects of sedation and drowsiness. Hydroxyzine can also interact with medications that affect heart rhythm, particularly those that cause QT interval prolongation, increasing the risk of arrhythmias.

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