Antibiotic Basics: What They Are and How They Work

Antibiotics are medicines that kill bacteria or stop them from growing. They don’t work on viruses, so taking them for a cold won’t help. Most antibiotics belong to a few families—penicillins, cephalosporins, macrolides, and fluoroquinolones—each with its own strengths and weaknesses.

When you start a course, the drug quickly drops the number of bad bugs, giving your immune system a chance to clear the rest. That’s why doctors prescribe a specific antibiotic tailored to the infection you have, based on lab tests or typical bacteria for that illness.

How to Use Antibiotics Safely

First, always follow the doctor’s instructions. Finish the full course—even if you feel better after a few days—because stopping early lets any surviving bacteria rebound and become harder to kill. Take the dose at the same times each day; setting an alarm can help.

If you miss a dose, take it as soon as you remember unless it’s almost time for the next one. Don’t double‑up; that can increase side effects without improving effectiveness. Store pills as advised—some need refrigeration, others are fine at room temperature.

Common Side Effects and When to Call a Doctor

Most people tolerate antibiotics well, but you might notice mild upset stomach, diarrhea, or a rash. These usually fade after a few days. If you develop severe diarrhea, especially watery with flecks of blood, it could be C. difficile infection—seek medical help right away.

Allergic reactions can range from itching to trouble breathing. If you notice swelling of the lips or tongue, hives, or difficulty breathing, treat it as an emergency and call 999.

Some antibiotics can interact with other meds, such as blood thinners or certain heart drugs. Always tell your pharmacist about every prescription and over‑the‑counter product you’re using.

Why Antibiotic Resistance Matters

Every time bacteria survive an antibiotic dose, they can develop tricks to avoid being killed—this is resistance. Over‑use (like taking leftovers for a new illness) and under‑use (stopping early) both push resistance. When common bugs become resistant, doctors have fewer options, and infections can become harder, longer, and more expensive to treat.

To fight resistance, only use antibiotics when a doctor says they’re needed, stick to the prescribed schedule, and never share pills with friends or family.

Quick Tips for Everyday Use

• Ask your doctor why a specific antibiotic was chosen.
• Write down the start and finish dates on a calendar.
• Take the medicine with food or water if it upsets your stomach.
• Keep a list of any side effects you notice and share it with your doctor.
• Never keep leftover antibiotics for future use.

By understanding how antibiotics work and using them responsibly, you protect your own health and help keep these life‑saving drugs effective for everyone. Got more questions? Talk to your pharmacist or doctor—they’re the best source for personalized advice.