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How do antibiotics work and when do you need them? An expert Q&A

11 Dec 2020

Do antibiotics make a cold go away faster? Can we build resistance to them? Infectious diseases expert Dr Annette Alaeus answers your questions

Antibiotics can be useful for some health problems. But doctors are increasingly reluctant to prescribe them.

Dr Annette Alaeus, a specialist in infectious medicine, explains why, and gives a super useful guide on what you need to know.

Can a cold be treated with antibiotics?

Antibiotics are medicines used to prevent and treat bacterial infections. They work by targeting harmful bacteria and prevent them from spreading.

‘Antibiotics don’t work for viral infections like colds and flu, coughs and sore throats (where these are caused by a virus),’ says Dr Alaeus.

What’s more, most mild bacterial infections get better on their own without using antibiotics, she explains.

‘The best thing you can do if you have a cold is to rest and drink plenty of fluids. And if needed, take paracetamol to reduce high fever.’

It’s normal to want to get rid of a cold as fast as possible. But using antibiotics won’t help. In fact, using them for viruses can put you at risk of getting a bacterial infection that’s resistant to antibiotics.

Can antibiotics help Covid-19?

Antibiotics cannot treat viruses, including Covid-19. But some people who become unwell with Covid-19 may develop a bacterial infection. In this case, antibiotics may be prescribed to treat that infection.

What is antibiotic resistance?

‘When antibiotics are overused, or used when they’re not needed, the bacteria they’re supposed to treat can change, adapt and develop resistance,’ says Dr Alaeus. ‘That can mean that eventually, antibiotics are no longer effective.’

This is known as antibiotic resistance and it’s now a problem worldwide. It can mean common infections like pneumonia, tuberculosis, blood poisoning (also known as septicemia), gonorrhoea and foodborne diseases are now becoming harder – and in some cases impossible – to treat.

When are antibiotics needed?

‘Ideally, antibiotics should only be used as a last resort where an infection is unlikely to clear up without antibiotics (for example, a Urinary Tract Infection that keeps recurring) or where it could carry a risk of more serious complications.

‘But antibiotics can really save lives when used in the appropriate way,’ Dr Alaeus says.

‘Having said that, taking antibiotics when you don’t need them can mean that they won’t work for you in the future, when you might really need them to treat a more serious condition,’ she explains.

If you’re unsure, a Livi GP can go through your symptoms and recommend the best treatment option.

Do antibiotics have a shelf life?

‘You should never use antibiotics that have passed the expiry date on the packet,’ Dr Alaeus advises. Once this has passed, there’s no guarantee it’s safe or effective.

What’s the best way to take them?

Antibiotics are available as tablets, capsules, or in liquid form. Creams, lotions, sprays or drops are used to treat skin, eye or ear infections, and injections or drops are prescribed for more serious infections.

‘Always take antibiotics as instructed on the packet, or by your doctor,’ says Dr Alaeus.

When you’re taking antibiotics, also keep in mind:

  • If you forget a dose, take it as soon as you remember and then continue to take your course of antibiotics as normal
  • Never take more than the recommended dose, as this will increase your chances of side effects like pain, diarrhoea, feeling sick and bloating
  • Some antibiotics don’t mix well with other medicines like the contraceptive pill or with alcohol. So, always check on the label or talk about any concerns to a GP
  • Finish your course as prescribed, even if you start to feel better, as this will allow enough of the antibiotics to clear any infection
  • Make sure you don’t take them for longer than necessary
  • Don’t take antibiotics that were prescribed for someone else

What about children and antibiotics?

Most childhood infections are caused by viruses, so children don’t often need antibiotics. When they do, doctors usually prescribe them based on a child’s age.

Do antibiotics really affect gut bacteria?

‘Antibiotics can harm the beneficial bacteria in your gut and this can cause yeast infections like thrush, as well as bloating and other digestive issues,’ says Dr Alaeus.

You need a balance of bacteria in your gut for good health, including a healthy immune system.

‘If you’re taking antibiotics, you can protect your gut by eating more probiotic foods,’ says Dr Alaeus. This is important for children too.

Good probiotic foods include sauerkraut, kefir, miso and live natural yogurt.

Try to include prebiotic foods like green leafy vegetables. These feed the healthy bacteria in your gut, encouraging them to grow.

This article has been medically approved by Dr Annette Alaeus, infectious diseases expert at Livi.

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