Antibiotics: when they help, and when they quietly make things worse

A patient came in last winter with a cough of four days. Before reaching us they had taken two different antibiotics bought from separate pharmacies, neither for a full course. The cough was viral and would have settled on its own. What they had instead was a disturbed gut, two partial exposures for every bacterium they happened to be carrying, and no more information than they started with.

This is not a story about one careless patient. It is close to the default in Pakistan, where antibiotics are sold without prescription and are among the most-consumed medicines in the world per head. The consequences are already arriving in our wards as typhoid and pneumonia that will not respond to the usual drugs.

What antibiotics do, and what they cannot

Antibiotics kill bacteria. They have no effect whatsoever on viruses. That single distinction settles most of the arguments people have with themselves at a pharmacy counter.

Almost always viral — an antibiotic will not help

• The common cold, with a runny nose and sneezing
• Most sore throats
• Most coughs and bronchitis, including a cough that lingers for two or three weeks after a cold
• Flu
• Most watery diarrhoea and vomiting illnesses

Often bacterial — an antibiotic may well be needed

• Urinary tract infection with burning and frequency
• Bacterial pneumonia
• Typhoid, confirmed on culture
• Streptococcal throat infection, in the specific pattern that suggests it
• Skin infections with spreading redness, an abscess, or an infected wound
• Infections after surgery or an injury

What an unnecessary course actually costs you

The harm is not theoretical, and it is not only about resistance in the abstract. It has personal, near-term components:

1. Your gut bacteria are disrupted for weeks to months, which is why diarrhoea, thrush and stomach upset are common afterwards — and occasionally something considerably worse.
2. Allergic reactions, tendon problems, and liver or kidney effects are real risks of these drugs. A risk taken for no possible benefit is a bad trade at any size.
3. Your own body's bacteria become more resistant. Next time you genuinely need an antibiotic — after an operation, in pregnancy, with a kidney infection — the straightforward option may no longer work.
4. If you take an antibiotic before a diagnosis, the culture that would have identified the organism is far more likely to grow nothing. We are then treating blind, which for a resistant typhoid is a serious disadvantage.

“Every antibiotic taken without a reason is borrowed from the course you will really need one day.”

If you are prescribed one, use it properly

• Finish exactly the course you were prescribed. Not longer, and not shorter — stopping early when you feel better leaves behind the hardiest bacteria, which are precisely the ones you did not want to select for.
• Keep the timing. Twice daily means roughly every twelve hours; the interval is what keeps the drug level high enough to work.
• Never take an antibiotic left over from a previous illness, and never one prescribed for someone else. The right drug for a chest infection is the wrong drug for a urine infection, and the wrong dose besides.
• Tell us about every allergy and every other medicine you take, including herbal preparations. Some interactions matter a great deal.
• Do not keep leftovers. If a course was correctly prescribed there should be none.

So what do you take for a viral illness?

Not nothing — just not an antibiotic. Rest, fluids, paracetamol for fever and aches, steam inhalation and honey in warm water for a cough (never honey for a child under one year), and salt-water gargles for a sore throat all genuinely help. Most viral illnesses are clearly improving by day five to seven.

When a fever does need to be seen

Short of that, come in the same day for a fever above 38.5°C lasting more than three days, a fever that settles and then returns, breathlessness on exertion, a cough with blood, severe throat pain that prevents swallowing, burning urine with back pain, or any fever in someone with diabetes, cancer treatment or a weakened immune system.

If you are standing at a pharmacy counter deciding between an antibiotic and a WhatsApp message to us, send the message. It costs nothing and it is the more informative of the two options.