Antibiotics

When should antibiotics be used?

Antibiotics do not work against infections caused by viruses such as colds, flu, most coughs or sore throats. Antibiotics are only effective against bacterial infections. They cannot help you recover from infections caused by viruses. Your doctor or nurse will only prescribe antibiotics when you need them, such as a kidney infection or pneumonia. Antibiotics can be life saving for infections such as meningitis. If you are having an operation, you may be given antibiotics to prevent an infection. This is known as prophylaxis.

How to take antibiotics

Antibiotics are usually taken by mouth but can be given into a vein, a muscle, or applied to the skin, eyes or ears as drops, lotion, or ointment. Some antibiotics should not be taken with certain foods. Others are best taken with no food in your stomach, usually an hour before meals or two hours after. Always follow the instructions on the label or patient information leaflet included in the medicine box. Do not give your antibiotics to friends, family or pets and do not keep any leftovers. If you have received more doses than you were prescribed, ask your pharmacist about how to dispose of the remaining medicines.

Resistance to antibiotics

Bacteria evolve rapidly – they adapt and find ways to survive the effect of antibiotics. They become ‘antibiotic resistant’, meaning the antibiotic will no longer work.

Taking antibiotics when they are not needed and not taking them correctly, for example, just when you remember or in a low dose, will lead to more bacteria becoming resistant to them. This is why it is important to finish the course of antibiotics even if you feel better, unless your doctor tells you to stop.

Special care

You should speak to your doctor before taking an antibiotic if you know you have any liver or kidney problems. Tell your doctor or pharmacist if you are pregnant or breastfeeding before taking any antibiotic.

Side effects

The most common side effects with antibiotics are diarrhoea, nausea and vomiting. Often you may get no obvious side effects from antibiotics, however if your symptoms persist, please contact your doctor.

Allergies

Some people can be allergic to antibiotics, particularly penicillin and similar medicines such as cephalosporins, and may experience side effects such as a rash, swelling of the face and tongue and difficulty breathing when they take antibiotics. This is called an anaphylactic reaction and it can be serious or even fatal. Always tell your doctor, nurse or pharmacist if you have had an allergic reaction to an antibiotic and remind them of your allergy before you receive any antibiotics.

Interactions with other medicines

Certain antibiotics can stop the contraceptive pill working properly. If you have diarrhoea or vomiting while taking an antibiotic, your pill might not be properly absorbed. In either case, you should use additional contraception while you are taking the antibiotic and for a further seven days after finishing the course. There are several important interactions between antibiotics and other medicines. It’s important to check with your doctor or pharmacist before you take other medicines or herbal remedies at the same time as your antibiotics.

Why can’t other antibiotics be used to treat resistant bacteria?

They can, but they may not be as effective, they may have more side effects and eventually the bacteria will become resistant to them too. We cannot be sure we will always be able to find new antibiotics to replace the old ones. In recent years fewer new antibiotics have been discovered, so we must look after the antibiotics we have by using them carefully. We cannot stop resistance occurring, but we can do a lot to slow it down and stop it spreading.