Hydroxyzine Viatris (Hydroxyzine Hydrochloride)

Hydroxyzine acts on histamine‑mediated pathways to relieve symptoms of several conditions.

• Allergic skin conditions: reduces rash, hives and itching associated with allergic reactions.
• Pruritus: alleviates intense itching caused by dermatologic or systemic disorders.
• Anxiety: provides short‑term relief of anxiety symptoms and tension.
• Nausea and vomiting: helps control nausea and vomiting in various clinical settings.

• Hydroxyzine hydrochloride selectively blocks peripheral and central histamine H1 receptors, decreasing the actions of endogenous histamine. The antagonism produces antiallergic effects, while its anticholinergic and sedative properties contribute to anxiolytic and antiemetic actions. The drug also exhibits mild inhibition of serotonin receptors, enhancing its therapeutic profile.

Hydroxyzine may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Drowsiness: feeling unusually sleepy or fatigued.
• Dry mouth: reduced salivation leading to a sticky sensation.
• Blurred vision: temporary difficulty focusing.
• Constipation: reduced bowel movements.
• Headache: mild to moderate head pain.
• Dizziness: sensation of light‑headedness or unsteadiness.

Serious or Rare Side Effects

• Anaphylaxis: severe allergic reaction with rash, swelling, and breathing difficulty.
• Cardiac arrhythmia: irregular heart rhythm, especially in patients with pre‑existing heart disease.
• Seizures: rare occurrence of convulsive episodes.
• Hepatic injury: signs of liver dysfunction such as jaundice.
• Blood dyscrasias: abnormal blood counts including agranulocytosis.
• QT prolongation: potential for life‑threatening ventricular tachycardia.

Before prescribing Hydroxyzine, clinicians should consider several safety factors.

• Assess sedation risk: evaluate patient’s need for alertness (e.g., driving, operating machinery).
• Use caution in the elderly: increased sensitivity to anticholinergic effects.
• Avoid concomitant alcohol: may potentiate central nervous system depression.
• Monitor hepatic function: adjust use in patients with liver impairment.
• Caution in glaucoma: anticholinergic activity can increase intra‑ocular pressure.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Hydroxyzine can interact with other medicines, altering its efficacy or safety.

Major Interactions (Avoid)

• CNS depressants (e.g., alcohol, benzodiazepines): may cause excessive sedation.
• MAO inhibitors: increase risk of hypertensive crisis and serotonin syndrome.
• Other antihistamines: additive anticholinergic and sedative effects.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole): may raise hydroxyzine plasma levels.
• CYP3A4 inducers (e.g., rifampin): may reduce hydroxyzine effectiveness.