Doxazosin (BPH)
Brand names: Cardura
This is doxazosin used for benign prostatic hyperplasia, relaxing prostatic and bladder-neck smooth muscle to relieve lower urinary tract symptoms. It is an alpha-1 adrenoceptor antagonist that also lowers blood pressure.
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 selectively blocks alpha-1 adrenoceptors in prostatic and bladder-neck smooth muscle, reducing outflow resistance and improving urinary flow.
Prescribing in practice
- First-dose and postural hypotension can occur, so start at a low dose, preferably at bedtime, and warn patients about dizziness on standing.
- Intraoperative floppy iris syndrome is a risk during cataract surgery, so the ophthalmic surgeon should be informed before the procedure.
- Caution is needed with other antihypertensives and PDE5 inhibitors owing to additive hypotension as outlined in the SPC.
Monitoring
Monitor blood pressure, particularly after initiation and dose changes, and review urinary symptom response.
Counselling the patient
- Rise slowly from sitting or lying to avoid dizziness, especially with the first doses.
- Tell your eye surgeon you take this medicine if you are having cataract surgery.
- Report fainting or palpitations.
Evidence & guidelines
Established for benign prostatic hyperplasia through trials demonstrating symptom improvement and increased urinary flow rates.
Reference: NICE NG97; 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.