Common side effects
These common side effects of furosemide happen in more than 1 in 100 people. There are things you can do to help cope with them:
Peeing more than normal
This will last for about 6 hours after taking furosemide. It's nothing to worry about, but if it's inconvenient for you, change the time you take furosemide to one that suits you better (provided it's no later than 4pm).
If peeing a lot is still a problem for you, talk to your doctor or pharmacist.
Feeling thirsty
It's important not to get dehydrated, but how much you drink will depend on why you're taking furosemide.
Check with your doctor how much liquid you can drink while you're taking this medicine.
Dry mouth
Chew sugar-free gum or suck sugar-free sweets.
Headaches
Make sure you rest and drink fluids – ask your doctor how much you can drink while taking this medicine. Do not drink too much alcohol.
Ask your pharmacist to recommend a painkiller. Talk to your doctor if the headaches last longer than a week or are severe.
Feeling confused or dizzy
If furosemide 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, ride a bike or use tools or machinery while you're feeling dizzy.
Feeling or being sick (nausea or vomiting)
Take furosemide with or just after a meal or snack. Take small, regular sips of water or squash so you do not get dehydrated (ask your doctor how much fluid you can drink). Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee.
If you take the combined contraceptive pill or the progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.
Speak to a doctor or pharmacist if any of these side effects bother you or last more than a few days.
Serious side effects
Some people have serious side effects after taking furosemide.
Tell your doctor or call 111 now if you get:
- unexplained bruising or bleeding, a high temperature, sore throat and mouth ulcers – these could be signs of a blood disorder
- severe stomach pain which could reach through to your back – this could be a sign of an inflamed pancreas (pancreatitis)
- severe pain in your side or blood in your urine – these could be signs of inflamed kidneys
- ringing in your ears (tinnitus) or loss of hearing
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to furosemide.
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 furosemide. For a full list, see the leaflet inside your medicine packet.
You can report any suspected side effect using the Yellow Card safety scheme.