How long will antibiotics take to work

Antibiotics can be useful for bacterial infections. But doctors are increasingly reluctant to prescribe them because of the risk they may no longer be effective.

Dr Annette Alaeus, a specialist in infectious medicine, explains why, and shares her advice on how to safely use antibiotics and prevent antibiotic resistance.

How do antibiotics work?

Antibiotics are medicines used to prevent and treat bacterial infections. They work by targeting harmful bacteria and prevent them from spreading. Most mild bacterial infections get better on their own without using antibiotics.

How long do antibiotics take to work?

Antibiotics start working straight away, but you may not feel better for 2 or 3 days, or maybe longer, depending on the type of infection you’re on antibiotics for. The important thing is to take them up until the end of the recommended course of treatment, even when you’re feeling better.

What's antibiotic resistance?

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

Antibiotic resistance is now a problem worldwide. It means common infections like pneumonia, tuberculosis, blood poisoning, gonorrhoea and foodborne diseases are now becoming harder – and in some cases impossible – to treat.

This is why doctors will no longer routinely prescribe antibiotics for conditions like chest infections, ear infections (for children) and sore throats, but only when it’s absolutely necessary.

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 (UTI) that keeps recurring) or where it could carry a risk of more serious complications.

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

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

Can a cold be treated with antibiotics?

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

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

It’s normal to want to get rid of a cold or flu as quickly 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.

The good news is that with rest and plenty of fluids your immune system will clear these viruses over time.

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.

How are antibiotics taken?

Antibiotics are available in many forms including tablets, capsules, liquid, creams, sprays or drops. The type of infection you have, and the location, will determine what form of antibiotics you’re advised to take.

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

6 tips for taking antibiotics safely

When you’re taking antibiotics, keep in mind these points:

1. Forgetting a dose

If you miss a dose, take it as soon as you remember and then continue to take your course of antibiotics as normal.

2. Stick to the recommended dose

Never take more than what a doctor recommends, as this will increase your chances of side effects like pain, diarrhoea, feeling sick and bloating.

3. Always check the label

There are several types of antibiotics and some don’t mix well with alcohol or other medicines like the contraceptive pill. Always check the label or talk about any concerns with a GP.

4. Finish the course

Make sure you complete the course of antibiotics you’ve been prescribed, even if you start to feel better. This will allow enough of the antibiotics to clear any infection.

5. Don’t share antibiotics

Never take antibiotics that were prescribed for someone else, as it may not be right for treating your specific infection.

6. Try probiotics

If you’re taking antibiotics, you can protect your gut by eating more probiotic foods or supplements. This will help protect you from side effects like thrush.

What can I do to prevent antibiotic resistance?

• Only use antibiotics when prescribed
• Never demand antibiotics if a doctor says you don’t need them
• Always follow a doctor’s advice when using antibiotics
• Never share or use leftover antibiotics

How can I prevent infections so I don’t need antibiotics?

The best way to prevent yourself from having to take antibiotics is to try to avoid infections in the first place. These steps will help:

• Wash your hands regularly
• Prepare food in a hygienic way
• Avoid contact with people who are sick
• Practice safer sex
• Make sure your vaccinations are up to date

This article has been medically approved by Dr Annette Alaeus, infectious diseases expert and Dr Bryony Henderson, Lead GP at Livi.