Infections That Do vs Don't Need Antibiotics
| Infection | Antibiotics Needed? | Reason |
|---|---|---|
| Common cold | No | Viral |
| Flu (influenza) | No (usually) | Viral; antivirals (oseltamivir) for high-risk |
| Sore throat (most) | No | 90% viral; antibiotics reduce duration by only 16 hours |
| Sinusitis (acute <10 days) | No | 90% viral; resolve with saline rinse and time |
| Chest infection (LRTI) | CRP-guided | CRP>100 → prescribe; CRP 20–100 → delayed prescription |
| Urinary tract infection | Yes (bacterial) | Nitrofurantoin or trimethoprim; culture-guided |
| Cellulitis | Yes | Flucloxacillin or cefalexin |
| Bacterial pneumonia | Yes | Amoxicillin first-line; macrolide if atypical |
| Appendicitis | Yes + surgery | Prophylaxis; IV in surgical management |
How Antibiotic Resistance Develops
- Patient takes antibiotics — kills sensitive bacteria, but resistant mutants survive
- Resistant bacteria multiply and colonise the gut microbiome
- Resistance genes transfer to other bacteria (via plasmids) — within days
- Resistant strains spread person-to-person, in hospitals, and globally
Complete the Course — But Not AlwaysEmerging evidence suggests shorter courses are as effective for many infections (e.g., 3-day UTI, 5-day pneumonia). 'Always complete the full course' is now nuanced — follow your doctor's specific prescription.
Never Use LeftoversDo not use leftover antibiotics from previous prescriptions. The infection may be different, the drug may not be appropriate, and old antibiotics can be degraded. Return unused antibiotics to your pharmacy.
Can I drink alcohol while taking antibiotics?
Alcohol doesn't reduce effectiveness for most antibiotics. However, metronidazole and tinidazole cause a severe reaction with alcohol (disulfiram-like reaction) — never combine. Alcohol worsens the side effects of many others and impairs immune recovery.
Why doesn't my GP always prescribe antibiotics?
Evidence shows antibiotics provide minimal benefit for most self-limiting respiratory infections. They have side effects (diarrhoea, allergy, C. difficile) and contribute to antibiotic resistance. Delayed prescribing (collect if not better in 48 hours) is evidence-based.
What is C. difficile and how is it related to antibiotics?
Clostridioides difficile is a bacterium that colonises the colon when normal gut flora is disrupted by antibiotics. It causes severe diarrhoea, colitis, and can be fatal in elderly patients. The highest-risk antibiotics: clindamycin, fluoroquinolones, co-amoxiclav.
What is a CENTOR score for sore throat?
A scoring tool to predict bacterial (Group A strep) tonsillitis: Tonsillar exudate, Tender anterior cervical lymph nodes, Absence of cough, Fever >38°C. Score 3–4 = positive throat swab; antibiotics considered. Score 0–2 = likely viral; no antibiotics.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.