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Tamsulosin

Medication alpha-1 blocker other
Aka: Harnal, Flomax
Brands seen in Singapore: Harnal OCAS, Tamsin, Tasulose, Tamsulosin-Teva
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Prescribed for urinary symptoms of an enlarged prostate
When to take
HealthHub: first tablet of a new dose at bedtime
Take with
HealthHub: with or without food; not crushed or chewed
Pros & cons
Pros
  • HealthHub: relaxes prostate and bladder-exit muscles
  • FDA: 0.4 mg once daily is the recommended bph dose
  • SG register: single-ingredient tablets are all 0.4 mg
Cons
  • HealthHub: dizziness, light-headedness or fainting
  • FDA: abnormal ejaculation among common adverse events
  • FDA: floppy iris syndrome during cataract surgery
Sources
  1. HSA — Listing of Registered Therapeutic Products (data.gov.sg open dataset, 5,511 rows, cached in full and filtered locally) · read 2026-08-27
    what it says
    “All 8 registered tamsulosin products read Forensicclassification 'Prescription Only'. The four single-ingredient ones are 0.4 mg 'TABLET, FILM COATED, EXTENDED RELEASE': SIN13696P Harnal OCAS · SIN15476P TAMSIN · SIN15573P TASULOSE · SIN16191P TAMSULOSIN-TEVA; the other four are dutasteride combinations.”
  2. NHS Medicines A-Z — Tamsulosin (index page, UK brand names) · read 2026-08-27
    what it says
    “Tamsulosin - Brand names: Contiflo XL, Faramsil MR, Flomaxtra XL, Pamsvax XL, Tabphyn MR … Find out how tamsulosin treats symptoms of an enlarged prostate and kidney stones, and how to take it.”
  3. HealthHub (Pharmaceutical Society of Singapore) — Tamsulosin: what is this medication for · read 2026-08-27
    what it says
    “Tamsulosin belongs to a group of medications known as alpha-1 blockers. It is used to treat benign prostatic hyperplasia … The medication works by relaxing the muscles of the prostate gland and bladder exit to help relieve these symptoms.”
  4. HealthHub — Tamsulosin: how should I take this medication · read 2026-08-27
    what it says
    “You may take this medication with or without food. Do not crush or chew the tablet as this can affect the release of medication into your body. The first tablet of a new dose should be taken at bedtime”
  5. HealthHub — Tamsulosin: what precautions should I take · read 2026-08-27
    what it says
    “Inform your healthcare professional if: You are allergic … has sulfonamide allergy … You have heart problems; You ever feel dizzy or faint when you stand up … You are undergoing cataract (cloudiness of the lens) eye surgery”
  6. HealthHub — Tamsulosin: common side effects · read 2026-08-27
    what it says
    “Dizziness, light-headedness or fainting … When taking the medication for the first time, restarting treatment, or starting to take a higher dose, these side effects may occur … Drowsiness … May affect your ability to drive”
  7. HealthHub — Tamsulosin: what food or medication should I avoid · read 2026-08-27
    what it says
    “Avoid drinking alcohol as it may increase the risk of dizziness, light-headedness or drowsiness.”
  8. US FDA label — tamsulosin hydrochloride capsules, section 2 Dosage and Administration, via openFDA drug/label.json · read 2026-08-27
    what it says
    “Tamsulosin hydrochloride capsules 0.4 mg once daily is recommended as the dose for the treatment of the signs and symptoms of BPH … the dose of tamsulosin hydrochloride capsules can be increased to 0.8 mg once daily”
  9. US FDA label — tamsulosin hydrochloride capsules, section 5 Warnings and Precautions, via openFDA drug/label.json · read 2026-08-27
    what it says
    “Should not be used in combination with other alpha adrenergic blocking agents … Exercise caution with concomitant administration of warfarin … Advise patients about the possibility and seriousness of priapism”
  10. US FDA label — tamsulosin hydrochloride capsules, section 6 Adverse Reactions, via openFDA drug/label.json · read 2026-08-27
    what it says
    “The most common adverse events (≥2% of patients and at a higher incidence than placebo) with the 0.4 mg dose or 0.8 mg dose were headache, dizziness, rhinitis, infection, abnormal ejaculation, asthenia, back pain”
  11. US FDA label — tamsulosin hydrochloride capsules, section 7 Drug Interactions, via openFDA drug/label.json · read 2026-08-27
    what it says
    “Tamsulosin hydrochloride capsules 0.4 mg should not be used with strong inhibitors of CYP3A4 (e.g., ketoconazole) … Concomitant use of PDE5 inhibitors with tamsulosin can potentially cause symptomatic hypotension.”
  12. US FDA label — tamsulosin hydrochloride capsules, section 5 Warnings and Precautions (cataract surgery, prostate cancer screening), via openFDA drug/label.json · read 2026-08-27
    what it says
    “Intraoperative Floppy Iris Syndrome has been observed during cataract and glaucoma surgery in some patients … Advise patients to be screened for the presence of prostate cancer prior to treatment and at regular intervals afterwards”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.