Tamsulosin belongs to a group of medicines called alpha-blockers. It's used to treat men with symptoms of an enlarged prostate (benign prostate enlargement).

It's also occasionally taken to treat kidney stones.

Tamsulosin is available on prescription and you can also buy it from pharmacies. It comes as tablets and capsules.

If you buy tamsulosin from a pharmacy make sure you see your doctor within 6 weeks of starting your treatment to make sure it's OK for you to carry on taking this medicine.

Tamsulosin is also known by brand names such as Flomax Relief and Flomaxtra XL.

Tamsulosin is sometimes combined with other ingredients to treat bladder problems and enlarged prostate. Brand names include Vesomni (with solifenacin) and Combodart (with dutasteride).

• Tamsulosin helps reduce the symptoms of an enlarged prostate gland by relaxing the muscles in the bladder and prostate so you can pee more easily.
• When you first take tamsulosin, it may make you feel dizzy or lightheaded. If this happens it's best to sit or lie down until your feel better.
• Tamsulosin is taken once a day, usually in the morning after breakfast or the first meal of the day.
• The main side effects of tamsulosin are feeling dizzy and problems when men ejaculate (such as little or no semen).

Tamsulosin can be taken by adults (aged 18 and over).

Do not give this medicine to children, unless on the advice of a specialist.

Tamsulosin is not suitable for some people. To make sure this medicine is safe for you, tell a doctor if you:

• have had an allergic reaction to tamsulosin or any other similar medicine in the past
• have orthostatic hypotension, a form of low blood pressure that can make you feel dizzy or lightheaded when you stand up
• have severe liver or kidney problems
• are having eye surgery for cataracts or glaucoma

Tamsulosin comes as slow-release tablets and capsules (also called modified release, prolonged release, MR or XL).

This means the medicine is released into your body gradually.

How much will I take?

The usual dose of tamsulosin for enlarged prostate and kidney stone is 400 micrograms, once a day. The word microgram is sometimes written with the Greek symbol μ followed by the letter g (μg). A microgram is 1,000 times smaller than a milligram (mg).

How to take it

Swallow your tamsulosin capsules or tablets whole with a glass of water.

Do not break, chew or crush them.

If you can, take tamsulosin in the morning, after breakfast or the first meal or snack of the day. This is so the highest levels of medicine are in your body during the day and gives you the most benefit when you are most likely trying to pee.

It's best to take it at about the same time each day.

What if I forget to take it?

If you miss a dose of tamsulosin, and you remember within 6 hours, take the missed dose as soon as you remember. If it's more than 6 hours, skip the missed dose and take your next dose at the usual time the next day.

Do not take a double dose to make up for a forgotten dose.

If you forget doses often, it may help to set an alarm to remind you.

You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Taking too much tamsulosin can lead to a decrease in your blood pressure and an increase in your heart rate. You may feel drowsy, faint and lightheaded.

If you need to go to hospital, do not drive yourself – get someone else to drive you or call an ambulance.

Take the tamsulosin packet, or the leaflet inside it with you plus any remaining medicine.

Like all medicines, tamsulosin can cause side effects, but many people have no side effects or only minor ones.

Side effects often improve as your body gets used to the medicine.

Common side effects

These common side effects happen in more than 1 in 100 people. They're usually mild and short-lived.

Talk to a doctor or pharmacist if these side effects bother you or last more than a few days:

• feeling dizzy – especially when you sit or stand up
• problems when men ejaculate - such as little or no semen

Serious side effects

Call a doctor straight away if you have:

• shortness of breath or difficulty breathing – these can be signs of lung problems
• yellow skin or the whites of your eyes turning yellow – these can be signs of liver problems
• bruising or bleeding easily – these can be signs of a blood problem

Serious allergic reaction

In rare cases, tamsulosin may cause a serious allergic reaction (anaphylaxis).

These are not all the side effects of tamsulosin. For a full list, see the leaflet inside your medicine packet.

What to do about:

• feeling dizzy – if tamsulosin makes you feel dizzy, stop what you're doing, and sit or lie down until you feel better. Do not drive, ride a bike or use tools or machinery if you're feeling dizzy. Do not drink alcohol as it will make you feel worse. Talk to a doctor if these side effects last more than a few days.
• problems when men ejaculate – if the amount you ejaculate is less than usual or you have no semen at all, you do not need to worry as this side effect is harmless. Talk to a doctor if it bothers you or does not get any better.

Tamsulosin is not usually recommended in pregnancy. It'’s not clear whether tamsulosin can harm your baby.

If you're taking tamsulosin for kidney stones and you're pregnant or trying to get pregnant, talk to a doctor about the benefits and possible harm of taking tamsulosin.

The doctor will be able to recommend the best treatment for you and your baby.

Tamsulosin and breastfeeding

If you take tamsulosin while breastfeeding there's a risk of the tamsulosin getting into your breast milk. This may mean your baby gets some side effects from the medicine.

Talk to a doctor if you want to breastfeed while taking tamsulosin.

There are some medicines that interfere with the way tamsulosin works.

Tell a doctor or pharmacist if you are taking:

• any other alpha-blockers such as doxazosin, alfuzosin, prazosin and terazosin – these may cause a decrease in your blood pressure
• other medicines for high blood pressure – taking them with tamsulosin can lower your blood pressure too much, which can make you feel dizzy or faint – tell your doctor if this keeps happening
• medicines for erectile dysfunction such as sildenafil, tadalafil or vardenafil
• medicines that may decrease the removal of tamsulosin from the body (for example ketoconazole, which is used for fungal infections and antibiotics such as erythromycin and clarithromycin
• other medicines that can lower your blood pressure – these include some antidepressants, nitrates (for chest pain), baclofen (a muscle relaxant), and co-careldopa and levodopa (for Parkinson's disease)

Taking tamsulosin with painkillers

It's OK to take take paracetamol, codeine and non-steroidal anti-inflammatory medicines (NSAIDs) such as ibuprofen while you're taking tamsulosin.

Mixing tamsulosin with herbal remedies and supplements

There's very little information about taking herbal medicines and supplements with tamsulosin.