Antibiotics: What They Treat and How to Use Them

Antibiotics are medicines that fight bacterial infections in people and animals, either by killing the bacteria or by making it hard for them to grow and multiply. They can be taken:

• by mouth — pills, capsules or liquids;
• on the body — creams, sprays or ointments for the skin, or eye ointment, eye drops or ear drops;
• by injection or intravenously (IV) — usually for more serious infections.

What they treat

Antibiotics treat only certain bacterial infections, such as strep throat, urinary tract infections and E. coli. Even some bacterial infections, including many sinus infections and some ear infections, may not need them. Taking antibiotics when they aren't needed won't help and can cause side effects. Let your health care provider decide the best treatment rather than asking for an antibiotic.

Antibiotics do not work on viral infections. Don't take them for:

• colds and runny noses, even when mucus is thick, yellow or green;
• most sore throats (strep throat is the exception);
• flu;
• most cases of bronchitis.

Side effects

Side effects range from minor to very severe.

• Common: rash, nausea, diarrhea and yeast infections.
• More serious: C. diff infections, which cause diarrhea that can lead to severe colon damage and sometimes death; severe, life-threatening allergic reactions; and antibiotic-resistant infections.

Call your provider if you develop any side effects.

Why use them only when needed

Besides side effects, unnecessary antibiotics contribute to antibiotic resistance: bacteria change so that the antibiotic no longer stops them, and they keep growing.

Using them correctly

• Follow the directions carefully.
• Finish the medicine even if you feel better — stopping too soon can let some bacteria survive and re-infect you.
• Don't save antibiotics for later.
• Don't share yours, and don't take antibiotics prescribed for someone else; doing so may delay the right treatment, make you sicker or cause side effects.

Sources

• MedlinePlus, National Library of Medicine: "Antibiotics," with information from the Centers for Disease Control and Prevention.