When Are Antibiotics Appropriate?

Antibiotics are one of the most important medical discoveries in human history. Before penicillin, a scratched knee could kill you. That is not hyperbole — it is a historical fact that we have collectively decided to forget because antibiotics made infections seem trivial. The problem is that overuse is slowly undoing that progress, and antimicrobial resistance (AMR) is now considered one of the most serious public health threats globally.

In Australia, we prescribe more antibiotics per capita than most comparable countries. The Australian Commission on Safety and Quality in Health Care estimates that up to 40% of antibiotic prescriptions in general practice are inappropriate — meaning they are prescribed for conditions that would resolve without them, or for viral infections where antibiotics have no effect at all. This is not about blaming doctors or patients. It is about understanding when antibiotics genuinely help and when other treatments are more appropriate.

How Antibiotics Work

Antibiotics target bacteria specifically. They work by either killing bacteria directly (bactericidal) or preventing them from reproducing (bacteriostatic), allowing your immune system to clear the infection. Different classes of antibiotics target different bacterial mechanisms — cell wall synthesis, protein production, DNA replication — which is why the choice of antibiotic matters. A doctor does not just prescribe "an antibiotic." They choose one that is effective against the most likely bacteria causing your specific infection.

Critically, antibiotics have zero effect on viruses. Viruses are fundamentally different organisms — they hijack your own cells to reproduce, and antibiotics cannot target that process. Prescribing antibiotics for a viral infection does not help you recover faster. It just exposes your body's bacteria to unnecessary antibiotic pressure, which is how resistance develops.

When Antibiotics Are Appropriate

Antibiotics are indicated when there is a confirmed or strongly suspected bacterial infection. Common conditions that benefit from antibiotic treatment include:

• Urinary tract infections (UTIs) — one of the most common reasons for antibiotic prescriptions, particularly in women. Uncomplicated UTIs respond well to short courses of targeted antibiotics.
• Bacterial throat infections (streptococcal pharyngitis) — confirmed with a clinical assessment or rapid antigen test. Most sore throats are viral, but strep throat requires treatment to prevent complications.
• Skin and soft tissue infections — cellulitis, infected wounds, and abscesses often require antibiotics. Mild skin infections may resolve with wound care alone.
• Bacterial pneumonia — a chest infection confirmed by clinical assessment and sometimes imaging. Most lower respiratory infections in otherwise healthy adults are viral.
• Middle ear infections (otitis media) — in children, many ear infections resolve without antibiotics. Guidelines recommend a watch-and-wait approach for mild cases, with antibiotics reserved for severe or persistent infections.
• Bacterial sinusitis — only when symptoms persist beyond 10-14 days or are severe. Most sinusitis is viral and resolves without treatment.
• Sexually transmitted infections — chlamydia, gonorrhoea, and syphilis require specific antibiotic treatment.

When Antibiotics Are Not Appropriate

The majority of infections that bring people to a doctor — or to a telehealth service — are viral. They are unpleasant, they make you feel terrible, and they resolve on their own. Antibiotics will not speed up recovery for:

• Colds and upper respiratory infections — caused by rhinoviruses and other viral agents. Average duration is 7-10 days regardless of treatment.
• Influenza — antiviral medications exist for flu but are only effective within 48 hours of symptom onset. Antibiotics are irrelevant.
• Most sore throats — around 85% of sore throats in adults are viral. A doctor can assess whether yours is likely bacterial.
• Acute bronchitis — usually viral, even when there is a productive cough with coloured sputum. Green mucus does not mean you need antibiotics — it means your immune system is working.
• COVID-19 — a viral infection. Specific antiviral treatments exist for high-risk patients, but antibiotics are not part of standard COVID management.
• Mild sinusitis — nasal congestion, facial pressure, and thick nasal discharge are common with viral upper respiratory infections and usually resolve within 7-10 days.

Antimicrobial Resistance in Australia

Antimicrobial resistance (AMR) occurs when bacteria evolve to survive antibiotic exposure. Every time antibiotics are used, there is selective pressure on bacteria — those that survive pass on their resistance genes. The more antibiotics are used (and misused), the faster resistance develops.

Australia has a National Antimicrobial Resistance Strategy, and the TGA actively monitors resistance patterns. The Australian Commission on Safety and Quality in Health Care publishes annual reports on antibiotic usage and resistance trends. The numbers are sobering: multi-resistant organisms are increasing in Australian hospitals and community settings, and some infections that were easily treatable 20 years ago now require more complex, more expensive, and more toxic antibiotic regimens.

This is not a distant, theoretical problem. AMR already kills more people globally than HIV/AIDS. In Australia, resistant infections contribute to longer hospital stays, more complications, and higher healthcare costs. The antibiotics that work today may not work tomorrow — and we are not developing new ones fast enough to keep pace.

Completing Your Course

When your doctor prescribes antibiotics, they choose a specific drug, dose, and duration based on the infection being treated and current RACGP guidelines. Completing the course as prescribed is important because stopping early may not fully eliminate the bacteria — leaving surviving organisms that have been exposed to the antibiotic and may develop resistance.

There has been some recent debate in medical literature about whether shorter courses might be appropriate for certain infections. The reality is that guidelines are regularly updated as evidence emerges, and for most common infections, the recommended course lengths are already quite short — 3-5 days for uncomplicated UTIs, 5-7 days for many respiratory infections. Your doctor prescribes the shortest effective course for your situation.

Common Side Effects

Antibiotics are generally safe, but they are not without side effects. Because they target bacteria indiscriminately, they affect your beneficial gut bacteria along with the infection. Common side effects include:

• Digestive upset — nausea, diarrhoea, and stomach cramps are the most common side effects across most antibiotic classes
• Thrush — disruption of normal bacterial flora can allow candida overgrowth, particularly vaginal thrush in women
• Skin rash — allergic reactions ranging from mild rash to severe hypersensitivity. Always inform your doctor of previous antibiotic allergies
• Photosensitivity — some antibiotics (particularly tetracyclines) increase sun sensitivity. Wear sunscreen if prescribed these in Australian summer
• Drug interactions — some antibiotics interact with other medications, including the oral contraceptive pill. Ask your doctor or pharmacist about interactions

Taking a probiotic during and after an antibiotic course may help reduce gut-related side effects, though the evidence is mixed. Eating yoghurt or fermented foods is a reasonable and harmless approach.

Antibiotic Stewardship and Your Role

Antibiotic stewardship is a coordinated effort to improve how antibiotics are prescribed and used. In Australia, the TGA, RACGP, and hospital antimicrobial stewardship programs all contribute to this effort. But stewardship is not just for healthcare professionals — patients have a role too.

• Do not pressure your doctor for antibiotics. If they say you do not need them, trust their clinical judgement.
• Do not save leftover antibiotics for next time. Different infections require different antibiotics.
• Do not share antibiotics with others. What worked for you may be wrong for someone else.
• Complete the full course as prescribed. Even if you feel better on day three of a five-day course.
• Ask questions. It is perfectly reasonable to ask your doctor why they are prescribing an antibiotic, or why they are not.

Getting the Right Assessment

A doctor assesses your symptoms, duration, and risk factors to determine whether antibiotics are appropriate. For some conditions — uncomplicated UTIs being the clearest example — telehealth assessment is well-suited because the diagnosis is based primarily on symptom history rather than physical examination. Other conditions may require a physical examination, lab tests, or imaging before antibiotics are prescribed.

The key principle is that a doctor should prescribe antibiotics based on clinical assessment, not patient request. A good doctor will explain why antibiotics are or are not appropriate for your situation — and that explanation is worth more than a prescription you do not need.