Like all medicines, spironolactone can cause side effects, although not everyone gets them.
Side effects often happen when you first start taking spironolactone and get better as your body gets used to the medicine.
Common side effects
These common side effects of spironolactone happen in more than 1 in 100 people. There are things you can do to help cope with them:
Feeling dizzy
If spironolactone makes you feel dizzy when you stand up, try getting up very slowly or stay sitting down until you feel better. If you begin to feel dizzy, lie down so that you do not faint, then sit until you feel better. Do not drive, cycle or use tools or machines while you're feeling dizzy.
This side effect usually wears off after a few days. Talk to your doctor if it carries on for longer.
Feeling or being sick
Take spironolactone with or just after a meal. It may help if you stick to simple meals and do not eat rich or spicy food. If you're being sick, take small, frequent sips of water so you do not get dehydrated (ask your doctor how much fluid you can drink).
If you take the combined contraceptive pill or progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.
This side effect usually wears off after a few days. Talk to your doctor about taking an anti-sickness medicine if it carries on for longer.
Muscle or leg cramps
If you get unusual muscle cramps that are not from exercise or physical work, talk to your doctor. You may need a blood test to check what is causing it.
Feeling tired or low in energy
Do not drive, cycle or use tools or machinery while you're feeling tired.
Some ways to increase your energy levels include exercise, eating a healthy diet and making sure you have a regular sleep pattern. There are self-help tips you can try to improve your energy levels.
If you are still feeling tired and low in energy, and this bothers you, or if it's getting worse, talk to your doctor.
Breast pain and breast enlargement, including in men
If this bothers you, talk to your doctor.
Serious side effects
Some people have serious side effects after taking spironolactone.
Tell your doctor or call 111 straight away if:
- the whites of your eyes turn yellow, or your skin turns yellow, although this may be less obvious on brown or black skin – these can be signs of liver problems
- you get a slow or irregular heartbeat, tingling feeling, muscle weakness or shortness of breath – these can be signs of potassium levels being too high
- you're peeing less that usual or have dark, strong smelling pee, feel thirsty or feel dizzy or light-headed – these can be signs of dehydration
- you have diarrhoea, are peeing less than usual, are feeling or being sick, and feel drowsy or confused – these can be signs of loss of kidney function
Serious allergic reaction
It's possible to have a serious allergic reaction (anaphylaxis) to spironolactone.
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 spironolactone. For a full list see the leaflet inside your medicines packet.
You can report any suspected side effect using the Yellow Card safety scheme.