Histexil (Hydroxyzine Hydrochloride)

Histexil is indicated for several clinical situations where its antihistamine, anxiolytic, and sedative actions are beneficial.

• Relief of itching, hives, and other symptoms of urticaria or allergic skin reactions.
• Short‑term management of anxiety or tension when non‑sedating agents are unsuitable.
• Pre‑operative or post‑operative sedation and anxiolysis to facilitate surgical procedures.
• Prevention or treatment of nausea and vomiting associated with allergic reactions or anesthesia.
• Adjunctive therapy for motion sickness when other options are ineffective.
• Control of pruritus in dermatologic conditions such as atopic dermatitis.

• Hydroxyzine hydrochloride acts as a selective antagonist of peripheral H1 histamine receptors, reducing the actions of histamine that cause itching, swelling, and vasodilation. It also exhibits anticholinergic activity and penetrates the central nervous system, where it produces sedative and anxiolytic effects by depressing neuronal activity, contributing to its utility in allergy, anxiety, and pre‑operative settings.

Histexil may cause a range of adverse reactions, from mild and transient effects that may resolve without intervention to rare but potentially serious events that require prompt medical attention.

Common

• Drowsiness or sedation, which may impair alertness.
• Dry mouth, leading to a feeling of thirst.
• Blurred vision, especially at higher doses.
• Constipation or reduced bowel movements.
• Headache, ranging from mild to moderate.
• Dizziness or light‑headedness.

Serious

• Severe allergic reaction (anaphylaxis, angioedema) requiring emergency care.
• Cardiac arrhythmias or QT interval prolongation, especially with pre‑existing heart disease.
• Seizures, particularly in patients with a seizure disorder.
• Significant liver injury, indicated by jaundice or abnormal tests.
• Acute urinary retention in individuals with prostate enlargement or bladder outlet obstruction.

When prescribing Histexil, clinicians consider several precautionary factors to minimize risk and ensure safe use.

• Known hypersensitivity to hydroxyzine or other antihistamines.
• Elderly patients, who may be more sensitive to sedative effects.
• Patients with glaucoma, urinary retention, or prostatic hypertrophy.
• Individuals with hepatic impairment, as metabolism may be reduced.
• Pregnancy and breastfeeding, because safety data are limited.
• Activities requiring mental alertness, such as driving, should be avoided until individual response is known.
• Concomitant use of other central nervous system depressants may increase sedation.

Histexil can interact with other medicines, potentially altering its effects or increasing the risk of adverse reactions.

Avoid

• Alcohol and other CNS depressants (e.g., benzodiazepines, opioids) because combined sedation may be excessive.
• Other antihistamines, which can increase anticholinergic burden.
• Monoamine oxidase inhibitors (MAOIs), due to possible additive central effects.
• Drugs that prolong the QT interval, increasing risk of cardiac arrhythmias.
• Strong anticholinergic agents, which may exacerbate dry mouth and urinary retention.

Use with caution

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) that may raise hydroxyzine levels.
• CYP3A4 inducers (e.g., rifampin, carbamazepine) that may lower hydroxyzine concentrations.
• Antidepressants (e.g., SSRIs, tricyclics) that may enhance sedation.
• Antihypertensive agents, as additive hypotensive effects may occur.
• Anticholinergic medications, requiring monitoring for excessive side effects.