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Alpha-1 adrenoceptor blocker (selective for alpha-1a) Pregnancy: Not indicated in females. Not applicable.

Tamsulosin

Brand names: Flomax MR, Stronazon MR

Adult dose

Dose: 400 micrograms once daily
Route: Oral (modified-release capsule — swallow whole after breakfast)
Frequency: Once daily (after breakfast)
Max: 400 micrograms/day
BPH lower urinary tract symptoms: 400 micrograms MR once daily after breakfast. Ureteric stone facilitation (medical expulsive therapy): 400 micrograms daily for 4 weeks. Do not crush or chew capsules.

Paediatric dose

Route: Oral
Frequency: Once daily
Max: Not licensed in children
Not licensed for use in children. No paediatric data.

Dose adjustments

Renal

No dose adjustment required for mild-moderate renal impairment; use with caution if eGFR <10.

Hepatic

No dose adjustment required for mild-moderate hepatic impairment; avoid severe hepatic failure.

Clinical pearls

  • IFIS (Intraoperative Floppy Iris Syndrome): alert ophthalmologist before any cataract surgery — may need to continue or stop tamsulosin as per specialist decision
  • More selective for lower urinary tract than doxazosin — less systemic hypotension
  • Retrograde ejaculation common (discuss with patient; resolves on stopping)
  • Medical expulsive therapy: 4-week trial for ureteric stones ≤10 mm increases passage rate
  • Take after breakfast to reduce first-dose hypotension

Contraindications

  • Orthostatic hypotension (history)
  • Severe hepatic impairment

Side effects

  • Orthostatic hypotension (especially first dose)
  • Dizziness
  • Retrograde ejaculation (common — impairs fertility)
  • Rhinitis
  • Intraoperative Floppy Iris Syndrome (IFIS) — if cataract surgery planned
  • Palpitations

Interactions

  • Phosphodiesterase-5 inhibitors (sildenafil, tadalafil) — additive hypotension risk
  • Other alpha-blockers — additive hypotension
  • CYP3A4 and CYP2D6 inhibitors — increased tamsulosin levels

Monitoring

  • Blood pressure (especially first dose)
  • Urinary symptoms (IPSS/AUA score)
  • Urinary flow rate if available

Reference: BNFc; BNF; NICE NG118 Lower Urinary Tract Symptoms; EAU Urology Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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