Antimicrobial resistance (AMR) is projected to cause 10 million deaths per year by 2050 without action — exceeding cancer mortality. Every unnecessary antibiotic prescription and every course taken incorrectly contributes to this threat. Understanding when antibiotics are and aren’t needed — and how to take them correctly — is one of the most impactful health literacy decisions you can make.
What Antibiotics Are and Aren’t For
Antibiotics kill bacteria. They have no effect on viruses. The most common infections for which antibiotics are requested — the common cold, influenza, most sore throats, most ear infections in adults, most acute bronchitis, most sinusitis — are viral in origin. Taking antibiotics for these conditions does nothing for the patient (there are no bacteria for them to act on) but does expose gut bacteria to the antibiotic, selecting for resistant strains through evolutionary pressure. The 2023 NICE Antimicrobial Prescribing Guidelines emphasise watchful waiting for most common self-limiting infections in healthy adults.
How Resistance Develops
Bacteria multiply rapidly and evolve through mutation. Any antibiotic exposure creates selective pressure — susceptible bacteria are killed; naturally resistant mutants survive and reproduce. Resistance genes are shared between bacteria — even between different species — through horizontal gene transfer (plasmid transfer). This means resistance can spread rapidly through bacterial populations. MRSA, C. difficile, carbapenem-resistant Enterobacteriaceae and XDR-tuberculosis are present in UK healthcare settings now. These are not hypothetical future threats.
How to Take Antibiotics Correctly
Complete the full course — the most important principle. Stopping when you feel better leaves the most resilient bacteria alive to multiply and potentially cause relapse with a more resistant population. Correct timing intervals — antibiotics maintain blood levels above the minimum inhibitory concentration (MIC) for the target organism. Taking twice-daily antibiotics once daily doesn’t maintain adequate levels. Follow the prescribed dosing schedule. Food interactions — amoxicillin and co-amoxiclav: with food (reduces GI effects). Tetracyclines: avoid dairy within 2 hours (calcium impairs absorption). Metronidazole and tinidazole: avoid all alcohol (severe reaction). Nitrofurantoin: with food (improves absorption, reduces nausea). Probiotic support — Saccharomyces boulardii and Lactobacillus rhamnosus GG taken alongside antibiotics and for 2 weeks after significantly reduce antibiotic-associated diarrhoea risk (including C. diff) and support microbiome recovery.
Frequently Asked Questions About Antibiotics
Should I keep leftover antibiotics for the next time I’m ill?
No — strongly inadvisable. The remaining antibiotic may be wrong for the next infection type. The dose may be insufficient for a full course. Self-prescribing antibiotics contributes to resistance. Leftover antibiotics should be returned to any pharmacy for safe disposal.
Does green mucus mean I need antibiotics?
No — green or yellow mucus (from the nose or chest) is produced by neutrophils fighting infection, which happens in both viral and bacterial infections. Colour is not a reliable indicator of bacterial cause. More relevant factors: fever above 38.5°C persisting beyond 3–4 days, systemic illness severity, and clinical examination findings. Most green-mucus respiratory infections are viral and self-resolving without antibiotics.
What is the “backup antibiotic prescription” approach?
NHS guidance increasingly supports a “delayed” or “back-pocket” prescription strategy for common infections — the GP provides a prescription but advises you to fill it only if symptoms worsen or don’t improve within 48 hours. Studies show this reduces antibiotic use by approximately 30% with no worse outcomes for most common infections. This approach is appropriate for uncomplicated UTI, mild sinusitis, acute bronchitis and ear infections in adults.
Are some antibiotics stronger than others?
Antibiotics have different spectrums of activity and mechanisms — not a simple “strong/weak” hierarchy. Broad-spectrum antibiotics kill more types of bacteria but are not necessarily “better” — they also destroy more beneficial bacteria, increasing C. diff risk and microbiome disruption. The ideal is the narrowest-spectrum agent effective against the specific organism, which is why antibiotic choice is based on the likely causative organism for each type of infection.
Browse cold and flu medicines at Huncoat Pharmacy. Related: Probiotics, Cold & Flu.
At Huncoat Pharmacy: Pharmacy First – no antibiotics needed for most infections, Private prescription service.