How does spironolactone work?
Spironolactone is a type of medicine called a potassium-sparing diuretic. Diuretics are medicines that make you pee more. Unlike other types of diuretic, spironolactone does not make your body lose potassium.
It works by stopping aldosterone (a hormone made by the adrenal glands) from working in a part of the kidneys called the distal tubules. This changes the salt and water balance in your body and increases the amount of water and salt you pee out.
Spironolactone also lowers the amount of testosterone that your body makes. It does this by affecting a protein that is involved in making testosterone.
When will I feel better?
For oedema, spironolactone usually starts working after 2 or 3 days, but it can sometimes take longer.
For high blood pressure (hypertension), it can take up to 2 weeks for spironolactone to work.
If you're taking it for high blood pressure you may not have any symptoms, and so you may not feel any different when you take spironolactone. This does not mean that the medicine is not working. It's important to keep taking it.
Are there any long-term side effects?
You can take spironolactone for a long time, but you will have to see your doctor or nurse occasionally for blood tests. These tests make sure the chemicals in your blood such as potassium are properly balanced.
How often you need to see your doctor or nurse for these tests will depend on the reason why you're taking spironolactone, if your dose has changed recently, how old you are, and if you have any other health problems such as kidney or liver disease.
What will happen if I stop taking it?
Talk to your doctor if you want to stop taking spironolactone. If you stop it too soon, your condition may get worse.
If you're taking it for oedema, stopping it can cause fluid to build up in your body again.
If you are taking it for high blood pressure (hypertension), stopping it can cause your blood pressure to rise again.
If you're bothered by side effects, your doctor may be able to prescribe you a different medicine.
Will I lose or gain weight?
If you're taking spironolactone for oedema, you will lose some weight as you pee out the extra fluid.
If you're losing a lot of weight soon after starting spironolactone, this can be a sign you are losing too much fluid and are becoming dehydrated. If you notice this happen, tell your doctor.
Do not take spironolactone to lose weight. Only take spironolactone if it's been prescribed, and only for the reason your doctor has prescribed it for you.
Can spironolactone be used for hormonal conditions such as acne?
Because it affects hormones, spironolactone is sometimes used to treat acne in women, excessive hair growth in women (hirsutism), and some types of hair loss (alopecia) in women, and to reduce testosterone in trans women.
It will need to be prescribed by a specialist for these conditions.
For acne, it can take up to 3 months before you notice any improvement.
For excessive hair growth and hair loss, it can take up to 6 months before you notice any improvement.
Will it affect my contraception?
Spironolactone does not affect any type of contraception, including the combined pill and emergency contraception.
Some hormonal contraceptives can reduce hormonal side effects of spironolactone, including breast pain and irregular periods.
However, some types of hormonal contraception are not usually recommended if you have conditions that spironolactone is used to treat, such as high blood pressure or liver disease.
Talk to your doctor if you're taking or want to start hormonal contraceptives.
If spironolactone makes you vomit, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.
Read more about what to do if you're on the pill and you're being sick.
Can I drive or ride a bike?
Spironolactone can make some people feel dizzy or tired, especially when they first start taking it or after taking a bigger dose. If this happens to you, do not drive a car or ride a bike until you feel better.
It might be best to stop driving and cycling for the first few days of treatment until you know how this medicine makes you feel.
It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.
Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while taking spironolactone. GOV.UK has more information on the law on drugs and driving.
Can I drink alcohol while taking spironolactone?
Spironolactone is used to treat conditions such as liver disease, where alcohol should be avoided. If you're taking spironolactone for these conditions, do not drink alcohol.
If you're taking it for other conditions, you can drink alcohol. But try to keep to the recommended guidelines of no more than 14 units of alcohol a week and no more than 2 units per day. A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
Spironolactone can make some people feel dizzy or sleepy. If this happens to you, try not to drink alcohol as it may make you feel worse.
Is there any food or drink I need to avoid?
Do not have low-sodium salt or salt substitutes, such as Lo-Salt, because they contain a lot of potassium. Using these with spironolactone can make your potassium levels too high.
Try to limit other food and drink that contains a lot of potassium, including bananas, avocados, pulses, nuts and salmon. Your doctor or dietitian can help you make a low potassium diet.