Antibiotics are used to treat or prevent some types of bacterial infection. They work by killing bacteria or stopping them from growing.
You can only get antibiotics on prescription.
Your GP will tell you if you need antibiotics or not.
Antibiotics can come as:
- tablets, capsules or a liquid that you drink - used to treat most types of mild to moderate infections
- creams, lotions, sprays and drops - often used to treat skin, eye or ear infections
- injections - given with a needle or through a drip (intravenously) and are used for more serious infections
Do not take antibiotics if you do not need them
Taking antibiotics when you do not need them can cause you harm. It can mean they will not work for you in the future. This is known as antibiotic resistance.
Uses of antibiotics
Antibiotics are used to treat bacterial infections that:
- are not serious but are unlikely to clear up without antibiotics - such as severe acne
- are not serious but could spread to other people if not treated - for example, the skin infection impetigo
- would respond quickly to antibiotics and speed up recovery
- carry a risk of serious complications - such as cellulitis or pneumonia
Antibiotics are sometimes given as a precaution to prevent an infection. This is called antibiotic prophylaxis.
For example, you may be prescribed antibiotics before an operation to reduce the chances of you getting an infection from the operation.
When not to take antibiotics
Antibiotics do not work for viral infections such as colds and flu, and most coughs.
Many mild bacterial infections get better on their own without using antibiotics. For example, an ear infection or sore throat.
If you take antibiotics when you do not need them, they may not work as well for you in the future.
This is because some types of bacteria are resistant to antibiotics. They are known as superbugs.
Check if you can take antibiotics
Most adults and children can take antibiotics.
Before starting antibiotics tell your GP or pharmacist if you:
- are taking other medicines - some antibiotics do not mix well with other medicines
- have other medical conditions - some antibiotics may not be suitable for you
- had an allergic reaction to medicine in the past
- are pregnant or breastfeeding
- are taking the contraceptive pill
Pregnant or breastfeeding
Not all antibiotics are safe for you and your baby.
Talk to your GP if you're pregnant or breastfeeding. They'll prescribe an antibiotic that is safe for you and your baby.
They will ask you:
- about the kind of infection you have
- if you are taking other medicines
- your stage in pregnancy
- if you have other illnesses
If you're pregnant or breastfeeding and think you may have side effects from antibiotics, talk to your GP or pharmacist.
Contraceptive pill
Some antibiotics do not mix well with the contraceptive pill and stop it working properly. For example, if you are prescribed rifampicin, you may need to use condoms as well.
Before you start taking antibiotics, ask your GP or pharmacist if your pill may be affected by the antibiotic.
Side effects from antibiotics can include getting sick (vomiting) and diarrhoea. If you get these side effects, you may need to use another form of contraception.
How and when to take antibiotics
Your GP or pharmacist will tell you when and how to take your antibiotics. Follow their advice. If you're not sure, ask them or read the advice on the packet or information leaflet.
Some antibiotics need to be taken on an empty stomach and some must be taken with food. Take your dose exactly as prescribed.
Contact your GP or pharmacist if you:
- feel worse at any time while taking antibiotics or want to stop taking them
- do not feel better after finishing the medicine
Only take antibiotics prescribed to you. Never borrow antibiotics.
If you forget to take a dose
If you forget to take a dose of your antibiotics, take it as soon as you remember. If it's almost time for the next dose, skip the missed dose. Do not take a double dose.
Take the rest of your antibiotics as normal.
If you take too much
There is a bigger risk of side effects if you take too many antibiotics or take doses closer together than recommended.
Non-urgent advice: Contact your GP or pharmacist if:
- you take 1 or more extra doses by mistake
- have side effects after taking an extra dose
Unused antibiotics
Do not keep leftover antibiotics. If you have some left over, ask your pharmacist if they can dispose of them.
Never share antibiotics that were prescribed for you with friends, family or pets.
Side effects of antibiotics
Antibiotics can cause side effects, but not everyone gets them.
Common side effects
There are things you can do to manage common side effects:
Feeling sick (nausea)
Stick to simple meals and do not eat rich or spicy food. It might help to take your antibiotic after you have eaten. But take it as your GP or pharmacist tells you.
Try drinking small, frequent sips of water. Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee.
Getting sick (vomiting)
Do not take any other medicines to treat vomiting without speaking to a pharmacist or doctor.
If you take contraceptive pills and you're getting sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.
Bloating and indigestion
Try not to eat foods that cause farting (flatulence), like lentils, peas, beans and onions.
You could also try eating smaller meals, eating and drinking more slowly, and exercising regularly.
There are medicines you can get without a prescription that can also help. Ask a pharmacist for advice.
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, contact your pharmacist or GP.
Loss of appetite
Eat when you would usually expect to be hungry. If it helps, eat smaller meals more often than usual. Snack when you're hungry. Have nutritious snacks that are high in calories and protein, such as dried fruit and nuts.
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.
Antibiotics can cause a type of diarrhoea called C. diff (Clostridioides difficile). In most cases, this is mild but it can be severe.
Talk to your GP or pharmacist if you have diarrhoea while taking an antibiotic.
If you take the combined contraceptive 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 for advice.
How long common side effects last
These side effects are usually mild and should pass when you finish your course of treatment.
Talk to your GP or pharmacist if side effects are severe or last a long time.
See the patient information leaflet that comes with your medicine for a full list of side effects.
Non-urgent advice: Find your patient information leaflet
Your patient information leaflet is the leaflet that comes with your medicine. You can find a digital version of the leaflet online.
Other types of side effects
There are other types of side effects that are not so common.
Thrush
Some people get thrush (candida) of the mouth or vagina after taking antibiotics.
This is because antibiotics can also kill your body’s good bacteria. Good bacteria normally stops you getting thrush, a fungal infection.
Talk to your GP or pharmacist if your mouth or vagina gets sore or has a white coating while you are on antibiotics.
Light sensitivity
Some antibiotics can make your skin sensitive to light. If your GP or pharmacist warns you about this side effect, it is important to keep safe in the sun.
Protect your skin from the sun
- When you go outside, wear clothes that cover you up, a hat and sunglasses.
- Use sunscreen or sunblock on your skin, with a high sun protection factor (SPF) of at least 30 to prevent sunburn.
- Use a sunscreen product for your lips.
- Never use sunlamps or tanning beds.
Severe aches and pains
In rare cases, some antibiotics can cause long-lasting or permanent side effects. They can impact your joints, muscles and nervous system.
Talk to your GP if you have tingling, numbness or pain in your tendons, muscles or joints.
Serious side effects
Some antibiotics can cause serious side effects, particularly if you are at risk of heart valve problems.
Urgent advice: Contact your GP urgently if you have:
- new heart palpitations (heartbeats that suddenly become more noticeable)
- sudden shortness of breath
Stop taking the antibiotics straight away.
Allergic reaction
You can have an allergic reaction to antibiotics, but this is rare.
In most cases, an allergic reaction is mild to moderate.
Antihistamines can help ease mild to moderate allergic reaction such as a raised, itchy skin rash (urticaria or hives).
Non-urgent advice: Contact your GP if
you're worried about symptoms of an allergic reaction including:
- a raised, itchy rash (urticaria or hives)
- coughing
- wheezing
- tightness of the throat, which can cause breathing difficulties
Severe allergic reaction
A severe allergic reaction (anaphylaxis) to antibiotics is rare but it can happen.
Emergency action required: Call 112 or 999 or go to an emergency department (ED) straight away if you:
- get a rash that is itchy, red, swollen, blistered or peeling
- are wheezing
- have tightness in your chest or throat
- have trouble breathing or talking
- have swelling in your face, lips, tongue or throat
You may need immediate treatment in hospital.
Taking antibiotics with other medicines
Some antibiotics do not mix well with other medicines. Tell your GP or pharmacist if you're taking other medicines. Ask if it is safe to take an antibiotic with your other medicine.
Antibiotics and alcohol
It's best not to drink alcohol when you're taking antibiotics. Alcohol can make antibiotic side effects worse. Some antibiotics, such as metronidazole, can cause serious side effects when mixed with alcohol.
Ask your GP or pharmacist if you can drink alcohol while you're taking antibiotics.
