Tamsulosin — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Tamsulosin?
Tamsulosin is a selective alpha-1A adrenergic receptor antagonist used primarily for the treatment of benign prostatic hyperplasia (BPH). This medication is commonly prescribed in New Zealand and is funded by Pharmac for benign prostatic hyperplasia.
What is Tamsulosin Used For?
Tamsulosin is prescribed for the symptoms of benign prostatic hyperplasia (BPH) — including urinary hesitancy, weak urinary stream, straining, incomplete bladder emptying, and nocturia. It is one of the most commonly prescribed medicines for BPH in New Zealand.
How Does Tamsulosin Work?
Tamsulosin selectively blocks alpha-1A adrenergic receptors in the smooth muscle of the prostate and bladder neck, causing them to relax. This reduces resistance to urinary flow and improves urinary symptoms, without the significant blood pressure-lowering effect of non-selective alpha-1 blockers like doxazosin.
How to Take Tamsulosin
Taken once daily, 30 minutes after the same meal each day. Swallow the capsule whole — do not crush, chew, or open it. The usual dose is 400 micrograms (0.4 mg) once daily. Response is usually seen within 1–2 weeks.
Common Side Effects of Tamsulosin
- Dizziness or light-headedness (especially on standing)
- Headache
- Abnormal ejaculation (retrograde ejaculation)
- Nasal congestion or runny nose
- Fatigue
- Palpitations
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Intraoperative floppy iris syndrome (IFIS) — inform your eye surgeon if you are scheduled for cataract surgery
- Severe allergic reaction (rash, angioedema)
- Orthostatic hypotension (sudden blood pressure drop on standing — rare but can cause fainting)
- Priapism (prolonged, painful erection — rare)
Drug Interactions
Tamsulosin may interact with other medicines. Always inform your doctor and pharmacist of all medications, supplements, and herbal products you are taking. Key interactions include:
- PDE-5 inhibitors (sildenafil, tadalafil — risk of hypotension)
- Other alpha-blockers (additive hypotension)
- Strong CYP3A4 inhibitors (e.g., ketoconazole — increase tamsulosin levels)
New Zealand Prescribing Information
Tamsulosin 400 microgram modified-release capsules (Flomax Relief®, Tamsin®, and generics) are funded by Pharmac for BPH. Men scheduled for cataract or other anterior segment eye surgery should inform their ophthalmologist as alpha-1 blockers — even if stopped prior to surgery — can cause IFIS, which complicates the procedure.
Frequently Asked Questions
How quickly does tamsulosin work for BPH?
Many men notice an improvement in urinary symptoms within 1–2 weeks of starting tamsulosin. The full benefit may take 4–8 weeks. Unlike finasteride, tamsulosin does not reduce prostate size but relieves symptoms quickly.
Will tamsulosin affect my blood pressure?
Tamsulosin is selective for alpha-1A receptors in the prostate, so it has much less effect on blood pressure than non-selective alpha-blockers like doxazosin. However, dizziness on standing can still occur, especially when starting treatment.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider with any questions you may have regarding a medical condition or medication. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for the most current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: