Antibiotic Options: How to Pick the Right One for Your Infection

Not every infection needs an antibiotic. That’s the first thing to know. Colds, most sore throats, and many coughs are viral. Antibiotics only work on bacteria, so the right choice starts with whether bacteria are the cause.

Doctors pick antibiotics based on where the infection is, how sick you are, any allergies you have, local resistance patterns, and test results when available. That decision balances effectiveness, safety, and the goal to avoid overusing broad drugs that can drive resistance.

Common antibiotic classes and when they’re used

Penicillins (amoxicillin, ampicillin) — Often first choice for ear infections, strep throat, and some skin infections. Safe for many people unless you have a penicillin allergy.

Cephalosporins (cephalexin, cefuroxime) — A step up in coverage. Used for skin infections, certain respiratory infections, and when penicillin can’t be used.

Macrolides (azithromycin, clarithromycin) — Good for some respiratory infections and for people allergic to penicillin. Resistance is increasing in some areas, so they aren’t always the first pick.

Tetracyclines (doxycycline) — Used for acne, tick-borne infections, and certain respiratory bugs. Avoid in young children and during pregnancy.

Fluoroquinolones (ciprofloxacin, levofloxacin) — Strong drugs used for complicated UTIs and some lung infections. They have rare but serious side effects, so doctors limit their use.

Sulfonamides (trimethoprim–sulfamethoxazole) — Common for UTIs and some skin infections. Watch for allergies and interactions with other medications.

Nitroimidazoles (metronidazole) — Targets anaerobic bacteria and some gut infections. Also used in veterinary care, like certain dog infections, under vet guidance.

Topical antibiotics — For minor skin infections or wounds. They reduce the need for systemic treatment when appropriate.

What patients should do and watch for

Ask why an antibiotic is needed and if testing (culture) is worth doing. If a doctor prescribes one, ask whether a narrow-spectrum drug will work. Bring a list of allergies and current medicines—some antibiotics interact with blood thinners, antacids, or other common drugs.

Take antibiotics exactly as directed. Finish the prescribed course unless a clinician tells you to stop. Don’t share leftovers or use someone else’s prescription. Using probiotics during and after a course can help reduce yeast or diarrhea for some people, but ask your provider which ones are sensible.

Watch for side effects: stomach upset, yeast infections, or loose stools. If you get a rash, swelling, breathing trouble, or severe diarrhea (especially with fever), seek medical help right away. Also contact your doctor if symptoms don’t improve within 48–72 hours.

Resistance matters. Use antibiotics only when needed, prefer targeted options, and follow instructions. That helps keep these medicines working when we truly need them.