Please could you give a brief introduction to antibiotics? What are they used for and how do they work?
Antibiotics are medicines used to treat infections or diseases caused by bacteria, such as some respiratory tract infections (including pneumonia and whooping cough), urinary tract infections, skin infections and infected wounds.
Antibiotics work by blocking vital processes in bacteria, killing the bacteria, or stopping them from multiplying. This helps the body's natural immune system to fight the bacterial infection.
Antibiotics can differ in the types of bacteria they work against.
Can antibiotics be used for treating viruses, such as colds and flu?
No, antibiotics don’t work against viruses. Many common respiratory tract infections — like colds and influenza — are caused by viruses, so antibiotics are of no use.
A course of antibiotics won’t actually help you to get over a cold or flu faster and won’t prevent your infection being passed onto other people.
If you are usually healthy and well, your immune system will take care of most respiratory tract infections (both viral and some bacterial infections) by itself.
Some people, such as those with weakened immune systems and medical conditions like diabetes, heart, lung or kidney disease, are more at risk from complications from a cold or flu, If you are at risk of the complications such as bacterial pneumonia, your doctor may prescribe antibiotics to prevent those complications but this does not treat the cold or flu virus itself.
What is antibiotic resistance? How does it arise and is it increasing?
Antibiotics have saved millions of lives since they were first introduced in the 1940s and 1950s. However, because they have been misused and overused, many antibiotics are now no longer effective against certain bacteria. This is a consequence of antibiotic resistance.
Antibiotic resistance happens when bacteria change to protect themselves from an antibiotic. They’re then no longer sensitive to that antibiotic. When this happens, antibiotics that previously would have killed the bacteria, or stopped them from multiplying, no longer work.
Antibiotic resistance is an ongoing global problem, and over the past 70 years many bacteria have become resistant to one or more antibiotics.
You’ve probably already heard about bacteria that are resistant to several different antibiotics, often referred to as ‘superbugs’. Methicillin resistant Staphylococcus aureus (MRSA) bacteria is a common example in hospitals, and it’s also reached superbug status in the community.
Bacteria that cause tuberculosis (Mycobacterium tuberculosis) are very hard to treat now too, and there are mounting concerns about antibiotic resistance with other bacteria that can cause diseases in the community, such as urinary tract infections and gonorrhoea.
Should we be worried about antibiotic resistance?
Absolutely and the World Health Organization has called this one of the biggest threats to human health today. Antibiotic resistance is a problem that affects us all, and we all need to be part of the solution.
With few new antibiotics being developed and antibiotic resistance increasing worldwide, it is becoming more difficult to treat infections. And Australia isn’t out of the picture when it comes to use of antibiotics — even if prescribing of antibiotics in Australia was reduced by 25%, Australia would still be above the OECD average.
The development of antibiotics was one of the most important advances in medicine. Many bacterial infections (e.g. tuberculosis and infected wounds) that previously had no effective treatment, and often killed people, became treatable with antibiotics.
If we don’t act now to curb antibiotic resistance, we could return to the way it was in the pre-antibiotic era, where common and life-threatening bacterial infections are no longer treatable.
Luckily there are things we can all do to help prevent antibiotic resistance.
What are some tips for preventing antibiotic resistance?
Firstly we must all understand that antibiotics won’t kill viruses such as colds and flu. You can be open with your health professional and tell them you only want an antibiotic if it is really necessary. By taking an antibiotic only when it’s needed, you’re helping the global fight against antibiotic resistance.
If you are prescribed an antibiotic when it is needed, you can still prevent antibiotic resistance by taking the right dose at the right time, as directed by your health professional.
It’s also very important not to keep any unused antibiotics or prescription repeats for another time. (instead, return leftover pills to your pharmacy for disposal and dispose of unused prescriptions) and never share antibiotics with others — they may have a different infection and using your antibiotic can lead to antibiotic resistance.
You can also take simple steps to avoid infections in the first place and prevent them from spreading to others. For example, staying at home while you’re unwell with a cold or flu, always covering your mouth when sneezing and coughing, disposing of tissues and washing your hands.
Do antibiotics interfere with how well hormonal contraceptives work?
Many women who use hormonal contraceptive methods often express concern that antibiotics may jeopardise their effectiveness. But in fact, there are only two antibiotics which are thought to affect how well some hormonal contraceptives work.
These are rifampicin – sold in Australia under the brand names Rifadin and Rimycin – and rifabutin – sold as Mycobutin. These antibiotics are usually only used to treat certain bacterial infections that are serious such as tuberculosis and MRSA, and for preventing meningitis (an infection around the brain or spinal cord), so most people won’t be prescribed them.
If women are prescribed rifampicin or rifabutin and they’re using a hormonal contraceptive pill, under-skin implant or vaginal ring, they’ll need to use extra contraceptive precautions (such as condoms) while taking these antibiotics and for 28 days after finishing the course.
Women using hormonal contraception are encouraged to get advice from their doctor or pharmacist so they’re reassured about the need to take precautions if prescribed an antibiotic.
And when it comes to taking antibiotics generally, talk to your doctor or pharmacist if you have a stomach upset while you’re on a medicine — persistent vomiting or severe diarrhoea, say for more than 24 hours, may reduce the effectiveness of a hormonal contraceptive pill and so you may need to use another contraceptive method.
Do antibiotics interfere with any other medications?
Yes, they can. Like medicines generally, antibiotics can interact with other medicines, even with foods and drinks.
For example clarithromycin, an antibiotic used to treat various infections including pneumonia, can interact with a number of medicines, including medicines for cholesterol, epilepsy, and erectile dysfunction. Clarithromycin can cause the levels of these other medicines to increase in your blood, which increases your chance of side effects.
Rifampicin and rifabutin can also reduce the effectiveness of some medicines other than hormonal contraceptives. Other antibiotics may reduce how well some medicines work for you too. Tetracycline antibiotics, for example, can bind to iron supplements in your gut to reduce the amount of iron you absorb into your body.
Some antibiotics can cause a severe reaction with alcohol involving nausea, vomiting, skin flushing, headache and a fast or irregular heart beat. These include metronidazole and tinidazole used to treat various infections including dental and vaginal infections, infected leg ulcers and pressure sores, and some stomach or gut infections including ulcers. You need to avoid drinking alcohol while taking these antibiotics, and for at least 24 hours after you’ve finished your course of metronidazole, and at least 72 hours after you stop taking tinidazole.
What side effects can there be with antibiotics?
Like all medicines, antibiotics have the potential to cause side effects. The most common side effects of almost all antibiotics are stomach problems such as diarrhoea, nausea and vomiting (affecting between 1 and 10 in every 100 people taking antibiotic).
For some women, taking antibiotics can upset the normal balance of bacteria in the vagina and this allows candida to grow, causing thrush. Rarely, taking antibiotics can result in a more serious imbalance involving overgrowth of Clostridium difficile bacteria in the gut (this affects between 1 and 10 in every 1000 people), which can cause anything from mild diarrhoea to life-threatening bowel inflammation).
Some antibiotics (e.g. penicillin or a related antibiotic such as amoxycillin) can cause allergic or hypersensitivity reactions such as hives (large, red, raised areas on the skin), fever and breathing problems. Very rarely (fewer than 1 in 1000 people), a person may experience a severe or immediate allergic reaction to the antibiotic (anaphylaxis).
Ask your doctor or pharmacist about the possible side effects of your medicine. You should also ask if there are any medicines you should not take with your antibiotic.
The consumer medicine information (CMI) for your medicine — available from your doctor, pharmacist or on the NPS MedicineWise website (www.nps.org.au) — also lists the most common side effects.
Why are some people allergic to some antibiotics?
We don’t know why this happens to some people and not others, but it may mean that you will have to avoid taking certain types of antibiotics (such as penicillins) in the future.
If you have developed a rash or hives, or have had a severe or immediate allergic reaction to any antibiotic in the past, make sure you tell your doctor so you don’t get the same kind of antibiotic prescribed again. Another type of antibiotic may not cause you the same problem.
On average, how well-educated are people on antibiotics?
NPS MedicineWise research earlier this year found that 1 in 5 Australians expect their doctor to prescribe antibiotics for themselves and/or their child when they have a cough or cold.
Of the 1013 Australians surveyed nationwide, 4 in 5 also said they expect a prescription from their GP when they have an ear, nose, throat or chest infection, with more than half (51%) saying they would ask their GP for one. Requests for antibiotics to treat their child’s cold or cough were double that of parents who would ask for one themselves (14% vs 6%), with fathers more likely to ask than mothers (22% vs 9%).
The survey also revealed a plethora of misconceptions when it comes to antibiotics with only half of respondents knowing that bacteria are becoming resistant to antibiotics. Only 40% knew antibiotics should not be taken for viruses and many (40%) did not know that taking antibiotics when they’re not needed contributes to antibiotic resistance. More than half did not know resistance increases when you don’t complete the course as directed, and in general, the youth audience had less knowledge.
Do you have any plans to try to improve people’s knowledge about antibiotics?
This year, NPS MedicineWise kicked off a five year campaign to encourage people to join the fight against antibiotic resistance.
The campaign has so far included a series of advertisements on television, in print and online, featuring everyday Australians donning ‘Resistance fighter’ t-shirts and taking simple actions to curb antibiotic resistance.
The campaign urges everyone to take these simple steps to becoming antibiotic resistance fighters:
Firstly, don’t expect or ask for antibiotics from your health professional if you have a cold or flu, as these are caused by viruses which antibiotics cannot and do not treat.
Secondly, if you are prescribed antibiotics for an infection, take them exactly as directed by your health professional, and know that not doing so increases antibiotic resistance.
Finally, always practice good hygiene to stop the spread of germs and encourage others to become resistance fighters too.
NPS is also running a campaign for health professionals. The first year of the campaign encourages health professionals to adhere more closely to therapeutic guidelines when prescribing antibiotics for respiratory tract infections and to communicate with patients about the dangers of overusing and misusing antibiotics
How else can people equip themselves in the fight against antibiotic resistance before we lose the power of antibiotics forever?
NPS MedicineWise has launched a free app for iPhone and iPad designed to help people take their antibiotics correctly and prevent antibiotic resistance. The ‘Antibiotics Reminder’ app is available on iTunes in Australia and allows you to set reminders for each dose of antibiotics, track whether doses are taken correctly and record progress in a daily recovery diary.
For more details about the Antibiotics Reminder app visit https://www.nps.org.au/
Where can readers find more information?
Learn more about joining the fight against antibiotic resistance at https://www.nps.org.au/, and join us on Facebook at www.facebook.com/NPSmedicinewise.
NPS MedicineWise also provides more information on antibiotics and treating respiratory tract infections at https://www.nps.org.au/.
About Dr Philippa Binns
Clinical adviser at NPS MedicineWise, Dr Philippa Binns has worked as a GP in metropolitan and regional centres, as well as in remote Aboriginal settings in the Northern Territory, Queensland, Victoria and NSW.
She has trained and worked as a public health physician and epidemiologist specialising in communicable disease control. She has a particular interest in improving the interface between primary care and population health. Philippa also enjoys volunteering at the beginning of each year to undertake student health checks at a school in Tanzania.
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