What Are Antibiotics?
Antibiotics are a class of medications used to treat infections caused by bacteria. They work either by killing bacteria directly (bactericidal) or by preventing bacteria from reproducing (bacteriostatic), allowing the immune system to clear the infection.
First developed in the 20th century, antibiotics transformed medicine — turning once-deadly infections into manageable conditions. However, decades of overuse and misuse have led to a growing global crisis: antibiotic resistance.
What Antibiotics Cannot Treat
This is one of the most important things to understand: antibiotics have no effect on viruses. This means they will not help with:
- The common cold or flu
- Most sore throats (the majority are viral)
- COVID-19 or other respiratory viruses
- Most cases of bronchitis
- Stomach bugs caused by viruses
Taking antibiotics for viral infections doesn't help — and it actively contributes to antibiotic resistance.
Common Types of Antibiotics
Different antibiotics target different types of bacteria. Doctors prescribe specific types based on the suspected infection:
| Antibiotic Class | Common Examples | Typical Uses |
|---|---|---|
| Penicillins | Amoxicillin, Flucloxacillin | Ear infections, chest infections, skin infections |
| Macrolides | Azithromycin, Clarithromycin | Chest infections, STIs, alternative for penicillin allergy |
| Tetracyclines | Doxycycline | Acne, Lyme disease, respiratory infections |
| Fluoroquinolones | Ciprofloxacin | Urinary tract infections, certain gut infections |
| Cephalosporins | Cefalexin | Skin, urinary tract, and respiratory infections |
How to Take Antibiotics Safely
Following antibiotic instructions carefully is essential for the treatment to work and to minimise side effects:
- Complete the full course — even if you feel better early. Stopping early can allow bacteria to survive and potentially develop resistance.
- Take at regular intervals — this maintains consistent levels of the drug in your system.
- Don't share antibiotics — a prescription is specific to your infection and your body.
- Avoid alcohol where advised — some antibiotics interact badly with alcohol (especially metronidazole).
- Be aware of common side effects — nausea, diarrhoea, and sensitivity to sunlight are possible; severe reactions like rashes warrant immediate medical attention.
Antibiotic Resistance: A Growing Problem
When bacteria are repeatedly exposed to antibiotics — especially unnecessarily — they can evolve and develop resistance mechanisms. Resistant bacteria are harder to treat and can spread to others. This is why healthcare professionals worldwide are cautious about prescribing antibiotics without a clear indication.
You can help by:
- Only taking antibiotics when prescribed by a doctor
- Never using leftover antibiotics from a previous prescription
- Not pressuring your doctor for antibiotics for viral illnesses
When to Seek Medical Advice
If you suspect a bacterial infection — fever that doesn't subside, worsening symptoms after a few days, signs of a urinary tract infection, or an infected wound — consult a healthcare professional. They can assess whether antibiotics are appropriate and, if so, which type is right for your condition.