Dosage and strength
Furosemide tablets come in 20mg, 40mg and 500mg strengths.
Liquid furosemide comes as 20mg, 40mg or 50mg strengths (in every 5ml).
The usual dose to treat adults with:
- high blood pressure is 40mg to 80mg a day
- heart failure or oedema is 20mg to 120mg a day
Doses are usually lower for people over 65 years as they may be more prone to side effects.
For babies and children, your doctor will use your child's weight or age to work out the right dose.
How to take it
Furosemide does not usually upset your stomach so you can take it with or without food.
Swallow the tablets whole with a drink of water.
If you're taking furosemide as a liquid, it will come with a plastic spoon or syringe to help you measure out the correct dose. If you do not have one, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.
When to take it
You’ll usually take furosemide once a day in the morning.
Sometimes you’ll take it twice a day – once in the morning and again at lunchtime. Occasionally, you take it every other day.
You do not need to take furosemide at the same time every day. You can occasionally take it at a different time if it's more convenient for you, for example if you need to go out for a few hours in the morning and you will not be near a toilet.
Try not to take furosemide too late in the day (after 4pm) or at night, otherwise you may have to wake up to go to the toilet. Your doctor or pharmacist will suggest the best times for you to take your medicine.
If you get ill while taking it
Contact your doctor if:
- you have a high temperature
- you’re sweating and shaking
- you’re being sick (vomiting) or have severe diarrhoea
Your doctor may recommend you stop taking furosemide for 1 to 2 days until you are better. You can start taking it again when you're eating and drinking normally.
If you take furosemide when you have an illness that makes you dehydrated, it can make the dehydration worse.
How long to take it for
Depending on why you're on furosemide, you may have to take it for a long time, even for the rest of your life.
If you forget to take it
If you forget to take your dose, take it as soon as you remember, unless it is after 4pm. In this case, leave out the missed dose and take your next dose at the usual time.
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 could also ask your pharmacist for advice on other ways to help you remember to take your medicines.
If you take too much
Taking too much furosemide can cause headaches, make you feel dizzy, have a pounding or irregular heartbeat and make you faint. You may also pee more than normal and feel thirsty.
The amount of furosemide that can lead to an overdose varies from person to person.
Urgent advice: Contact 111 for advice now if:
You take more than your prescribed dose of furosemide and:
- feel unwell
- you are over 65 (even if you feel well)
- you have kidney, liver or heart failure (even if you feel well)
Go to 111.nhs.uk or call 111.
Call 111 if you need advice about a child under the age of 5 years.
If you go to A&E, take the furosemide packet, or the leaflet inside it, plus any remaining medicine with you.
Stopping furosemide
Talk to your doctor if you want to stop taking furosemide.
Stopping it may cause your blood pressure to rise, and this may increase your risk of heart attack and stroke.
If you're bothered by side effects, your doctor may be able to prescribe you a different medicine.