α1-adrenergic antagonist

Terazosin

Brand names: Hytrin

Terazosin is a selective alpha-1 adrenoceptor antagonist used in benign prostatic hyperplasia and, less commonly, hypertension.

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 blocks postsynaptic alpha-1 adrenoceptors, relaxing smooth muscle in the bladder neck, prostate and vasculature, easing urinary flow and lowering blood pressure.

Prescribing in practice

First-dose hypotension and syncope can occur, so introduce gradually, ideally with the first dose taken at bedtime.
Use with caution in the elderly and in those at risk of falls because of orthostatic hypotension.
It can cause intraoperative floppy iris syndrome, so inform the ophthalmologist before cataract surgery.

Monitoring

Monitor blood pressure, particularly for postural drop after initiation and dose increases.

Counselling the patient

Take the first dose at bedtime and rise slowly to reduce dizziness.
Report fainting, dizziness or palpitations.
Tell your eye surgeon you take this medicine before any cataract operation.

Evidence & guidelines

Alpha-blockers are established options for benign prostatic hyperplasia symptoms and are used in line with current UK guidance.

Reference: NICE NG106; 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).

Curated clinical cross-links plus same-class fallbacks.

Pathways