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 of tamsulosin happen in more than 1 in 100 people. They're usually mild and only last a short time. There are things you can do to help cope with them:
Feeling dizzy or sweating – especially when you sit or stand up
If tamsulosin makes you feel dizzy or start sweating, 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. It's best not to drink alcohol, as it will make you feel worse.
If you're still feeling dizzy after a few days speak to your doctor.
Problems ejaculating
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.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
Tell your doctor or call 111 straight away if:
- you faint, or pass out for a short time
Immediate action required: Call 999 or go to A&E now if:
- you get any new swelling developing under your skin's surface, in your mouth, or on your face, lips, tongue or throat – this could be a symptom of angioedema
- you get a painful erection that lasts 2 or more hours
Serious allergic reaction
In rare cases, tamsulosin may cause a serious allergic reaction (anaphylaxis).
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Other side effects
These are not all the side effects of tamsulosin. For a full list, see the leaflet inside your medicine packet.
You can report any suspected side effect using the Yellow Card safety scheme.