Dosage and strength
Spironolactone tablets come in strengths of 12.5mg, 25mg, 50mg and 100mg.
How much spironolactone you need to take depends on why you're taking it. Your dose may need to be changed a few times before you find the dose that's right for you.
The usual dose for adults is:
- heart failure – 25mg once a day as a starting dose. Depending on how well it works for you, the dose can be from 25mg every other day to 50mg once a day
- build-up of fluid caused by liver disease (ascites) – between 100mg and 400mg a day
- oedema caused by heart failure – 100mg a day as a starting dose. Depending on well it works for you, the dose can be between 25mg and 200mg a day
- nephrotic syndrome (a condition caused by kidney disease) – between 100mg and 200mg a day
- high aldosterone levels – 400mg a day as a starting dose, for a few days to a few weeks, to check if high aldosterone levels are the cause of your symptoms. Once confirmed, the long-term dose can be between 100mg and 400mg a day
- high blood pressure (hypertension) – 25mg a day
Doses are usually lower for people over 65 years as they may be more likely to get side effects.
For babies and children, your child's doctor will use your child's weight or age to work out the right dose.
How to take it
You'll usually take spironolactone once a day in the morning.
If you're taking a high dose you might need to take spironolactone twice a day. If you're taking it twice a day, make sure you take the second dose no later than 4pm. Taking it later than this may mean you have to wake up in the night to pee.
Some people only need to take it once every 2 days.
Take spironolactone with a meal to help reduce side effects such as feeling sick.
Swallow the tablets whole with a drink of water. Do not chew them.
How long to take it for
Depending on the reason why you're taking spironolactone, you may have to take it for a long time, even for the rest of your life.
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 bothered by side effects, your doctor may be able to prescribe you a different medicine.
If you forget to take it
If you forget to take a dose of spironolactone, take it as soon as you remember, unless it's after 6pm. In this case, skip the missed dose and take your next dose at the usual time the next day.
Do not take 2 doses to make up for a forgotten dose.
If you often forget doses, it may help to set an alarm to remind you. You can also ask your pharmacist for advice on other ways to help you remember to take your medicine.
If you take too much
Taking too much spironolactone can make you pee more than usual and feel thirsty. It can also cause symptoms including feeling or being sick, diarrhoea, and feeling confused or dizzy.
Too much spironolactone can cause the potassium levels in your blood to become too high. Signs of high potassium levels include:
- a slow or irregular heartbeat
- a tingling feeling
- muscle weakness
- shortness of breath
Urgent advice: Contact 111 for advice now if:
you take more than your prescribed dose of spironolactone and you:
- feel unwell
- are over 65 (even if you feel well)
- have kidney, liver or heart failure (even if you feel well)
Go to 111.nhs.uk or call 111. Call 111 if you're asking about a child under 5 years.
If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance.
Take the spironolactone packet, or the leaflet inside it, plus any remaining medicine with you.