Like all medicines, labetalol can cause side effects in some people, but many people have no side effects or only minor ones.
Side effects often improve as your body gets used to the medicine.
Common side effects
These common side effects of labetalol happen in more than 1 in 100 people. They're usually mild and go away by themselves. There are things you can do to help cope with them:
Feeling sleepy, dizzy or weak
If labetalol makes you feel dizzy or weak, stop what you're doing and sit or lie down until you feel better. Do not drive, cycle or use tools or machinery if you're feeling sleepy or dizzy. Do not drink alcohol as it will make you feel worse.
Talk to your doctor if you feel dizzy all the time or this side effect lasts longer than a week.
Headaches
Make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller.
Headaches usually go away after the first week of taking labetalol. Talk to your doctor if the headaches last longer than a week or are severe.
Cold fingers or toes
Put your hands or feet under warm running water, massage them and wiggle your fingers and toes. Do not smoke or have drinks with caffeine in, as this can make your blood vessels narrower and further restrict blood flow to your hands and feet. Try wearing mittens (they're warmer than gloves) and warm socks. Do not wear tight watches or bracelets.
Feeling sick or being sick (nausea or vomiting)
Stick to simple meals and do not eat rich or spicy food. It might help to take your labetalol after a meal or snack. Drink plenty of fluids, such as water or squash, to avoid dehydration. Take small, frequent sips if you are being sick. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.
Do not take any other medicines to treat vomiting without speaking to a pharmacist or doctor.
If you take the combined pill or the progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.
Diarrhoea
Drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.
Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.
If you take the combined pill or the progestogen-only pill and you have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.
Stomach pain
Try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your stomach may also help. If you are in a lot of pain, speak to your pharmacist or doctor.
Talk to your doctor or pharmacist if any of these side effects bother you or last more than a few days.
Serious side effects
It does not happen often, but some people have serious side effects when taking labetalol.
Tell a doctor or call 111 now if:
- you have shortness of breath with a cough that gets worse when you exercise (like walking up stairs), swollen ankles or legs, or an irregular heartbeat – these are signs of heart problems
- you have shortness of breath, wheezing and tightening of the chest – these can be signs of lung problems
- the whites of your eyes turn yellow, or your skin turns yellow although this may be less noticeable on brown or black skin, or you have pale poo or dark pee – these can be signs of liver problems
- you get unexplained bruising, or you bruise more easily than usual – these can be signs of low numbers of platelets in your blood (thrombocytopenia)
Immediate action required: Call 999 now if:
- you get chest pain
Chest pain is a possible sign of a heart attack and needs to be checked out as soon as possible.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Serious allergic reaction
In rare cases, labetalol may cause a serious allergic reaction (anaphylaxis).
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.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Other side effects
These are not all the side effects of labetalol. For a full list, see the leaflet inside your medicine packet.
Reporting side effects
You can report any suspected side effect using the Yellow Card safety scheme.
Visit the Yellow Card website for more information about reporting side effects.