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Antihistamine (H1) — Anxiolytic / Sedative

Hydroxyzine

Brand names: Atarax, Ucerax

Hydroxyzine is a sedating first-generation antihistamine used for the short-term management of anxiety and for symptomatic relief of pruritus.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is an antagonist at peripheral and central histamine H1 receptors, producing sedative, anxiolytic and antipruritic effects.

Prescribing in practice

  • It can prolong the QT interval and has been associated with torsades de pointes, so avoid in patients with known QT prolongation or significant cardiac risk factors and use the lowest effective dose for the shortest time.
  • Marked sedation and antimuscarinic effects can occur, so use with caution in the elderly and in those with urinary retention, glaucoma or prostatic enlargement.
  • Avoid concurrent use with other medicines that prolong the QT interval or have additive sedative effects.

Monitoring

Assess cardiac risk factors before starting and review for excessive sedation and antimuscarinic effects, with ECG consideration in those at risk of QT prolongation.

Counselling the patient

  • Warn that drowsiness is common and may impair driving and skilled tasks.
  • Avoid alcohol while taking this medicine.
  • Seek urgent advice if palpitations or fainting occur.

Evidence & guidelines

The MHRA has highlighted the risk of QT-interval prolongation and torsades de pointes with hydroxyzine, supporting cautious use as detailed in current prescribing references.

Reference: NICE NG106 (GAD); MHRA Hydroxyzine Safety Update 2015; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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