Antibiotics

Antibiotics are medicines that treat infections and diseases caused by bacteria. Penicillin is a well-known antibiotic.

Antibiotics do not work against viruses, which are the cause of most colds, flu and COVID-19.

Antibiotics work by killing the bacteria or stopping them from multiplying. This helps your immune system to fight the infection.

Why are there different types of antibiotics?

Some antibiotics work against different types of bacteria:

• Broad-spectrum antibiotics — such as amoxicillin — work against many types of bacteria.
• Narrow-spectrum antibiotics — such as penicillin — only work against a few types of bacteria.

Your doctor will choose an antibiotic that is best suited to treat your infection.

How do doctors know which antibiotics to use?

Sometimes, your doctor will choose an antibiotic based on what is likely to work.

At other times, your doctor will suggest you have tests. These will show which types of bacteria are causing your infection. This information helps them to choose the antibiotics that will be most effective.

Like all medicines, antibiotics can cause side effects.

Some common side effects are:

• diarrhoea
• nausea and vomiting
• thrush infections in your mouth or vagina

Less common side effects are:

• ongoing diarrhoea
• allergic reactions — most often skin reactions

There is some evidence that taking probiotics during a course of antibiotics can reduce antibiotic-associated diarrhoea. Probiotics are available in supermarkets, pharmacies and health food stores.

Ask your doctor or pharmacist about possible side effects from your medicine.

What happens if I'm allergic to antibiotics?

Like all medicines, when taking antibiotics you should follow the instructions that your doctor or pharmacist gives you. You should:

• take your antibiotics at the right time
• take them for as long as you are told to, even if you are feeling better
• do not take more than you have been told to (even if there are tablets left)
• return tablets that you don't use to the pharmacy

Do not share antibiotics with other people.

Most antibiotics are given by mouth, either as a liquid or a tablet. Some antibiotics can be put directly in your eyes as eye drops or ointment.

If you are in hospital, you might be given antibiotics through a drip (intravenously). Your doctor will choose the best way for you to get your medicine.

You might want to ask your doctor if there are any medicines you should not take with your antibiotics. This information can also be found in the Consumer Medicine Information (CMI) that comes with your medicine.

The COVID-19 pandemic has changed the supply chain of many medicines, including antibiotics.

If you cannot get the medicine that you need, speak to your pharmacist or doctor. They can advise on alternatives.

For more information, visit Therapeutic Goods Administration (TGA) (Opens in new tab).

Antibiotic resistance happens when bacteria change to protect themselves from an antibiotic. This means that the antibiotic no longer works to kill the bacteria.

This can happen naturally. But the main cause of antibiotic resistance is antibiotic use.

Antibiotic resistance can happen by:

• using antibiotics when they're not needed
• not taking antibiotics properly — such as missing doses or not finishing the course

Antibiotic resistance means that some bacterial infections may cause serious illness or death.

What are 'superbugs'?

'Superbugs' is a term used for bacteria that are resistant to many types of antibiotics. These infections are very hard to treat.

Examples of superbugs are:

• methicillin-resistant Staphylococcus aureus (MRSA)
• multi-resistant gram-negative bacilli (MRGN)
• vancomycin-resistant enterococci (VRE)

The last antibiotic treatment for gonorrhoea has already started to fail in Australia.

What happens if I get an antibiotic-resistant infection?

If you get an antibiotic-resistant infection:

• you will be sick for longer
• you may get more complications from the infection
• you may need more complex care
• you might be infectious for longer so may pass your infection on to other people

Australia has one of the highest rates of antibiotic use in the world. You can help slow down antibiotic resistance by:

• not asking for antibiotics when you have a cold or the flu — antibiotics do not treat viral infections
• taking the antibiotics as prescribed by your doctor, for as long as you need them
• having good hygiene practices to help stop the spread of infections

Antibiotic resistance can't be totally stopped, but you can help slow it down by using antibiotics sensibly.

Why did I get antibiotics when I had surgery?

Sometimes antibiotics are prescribed to stop infections happening. This might happen when you have surgery or a dental procedure.

In Australia, doctors and nurses are working together to review this practice. By lowering the use of antibiotics, they will help lower antibiotic resistance.

Learn more about antimicrobial resistance (Opens in new tab).

Learn about the safe use of antibiotics on the Australian Commission on Safety and Quality in Health Care website (Opens in new tab).

The Health Translations website has information about antibiotic resistance (Opens in new tab) in languages other than English.

The National Antibiotic Allergy Network has information on antibiotic allergies and side effects (Opens in new tab) in languages other than English.

You can also call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with, 24 hours, 7 days a week.