What are bacteria?
Bacteria are tiny organisms not visible to the human eye. Billions of bacteria live in and on people, animals and plants at all times. Most bacteria are helpful to us; some are harmful and cause infections.

What are antibiotics?
Antibiotics are prescription drugs that attack bacterial germs. They are powerful substances which can kill or disable disease causing bacteria.

Here are the different types of antibiotics.

How safe are antibiotics?
Antibiotics are generally safe and should always be taken as prescribed by your doctor; however,

  • Antibiotics may alter the effectiveness of other medications and cause side effects or allergic reactions.

  • Antibiotics can kill most of the bacteria in your body that are sensitive to them, including good bacteria. By destroying the bacterial balance, it may cause stomach upsets, diarrhea, vaginal infections, or other problems.

  • If you take antibiotics unnecessarily you may contribute to the development of antibiotic resistance. If you become sick and your bacteria are resistant to your prescribed antibiotic, your illness lasts longer and you may have to make return office and pharmacy visits to find the right drug to kill the germ. For more serious infections it is possible that you would need to be hospitalized or could even die if the infection could not be stopped. Also, while the resistant bacteria are still alive, you act as a carrier of these germs, and you could pass them to friends or family members.

When should you take antibiotics?
Antibiotics are prescribed for illnesses caused by bacteria, not by viruses. The common cold and flu are caused by viruses, not by bacteria. Antibiotics do not work against viruses, and should not be taken for cold or flu. When used prudently, antibiotics are a powerful medical tool to thwart bacterial diseases. Prudent use includes taking antibiotics only for diagnosed bacterial infections and following the precise directions on the prescription. (See About bacteria and antibiotics.)

How does a physician decide which antibiotic to prescribe?
Physicians examine patients and consider their symptoms in order to tell if they should prescribe an antibiotic and, if so, which one. Physicians can also take a culture to see if bacteria are causing a particular illness, such as a throat culture to determine the presence of "strep throat." For hospital infections and some community-acquired infections, the doctor will obtain an "antimicrobial susceptibility report" that indicates which families of antibiotic drugs are useful for the particular bacteria recovered from the infection. If the cause of the infection is unclear, but suspected to be due to bacteria, the doctor may prescribe a broad-spectrum antibiotic that is useful for controlling a wide variety of bacterial types. The physician may choose either a generic or trade-name (non-generic) antibiotic depending on the individual circumstances.

What kind of questions should I ask my doctor if I am prescribed antibiotics?
If your doctor prescribes antibiotics, you should ask--

  • Why do I need an antibiotic?

  • What is this particular antibiotic supposed to do?

  • Is this drug likely to cause any side effects?

  • Is there anything I can do to prevent these side effects?

  • Should I take the drug at a specific time? With or without food?

  • How much does it cost?

  • Does this drug interfere with the effectiveness of other medication? (i.e., birth control pills)

  • Do I need to avoid alcohol or other foods?

Also, be sure to tell your doctor about any--

  • previous adverse drug reactions

  • special diet

  • allergies

  • health problems

  • chance of pregnancy

When I start feeling better can I stop taking the antibiotic?
No. Your prescription is written to cover the time needed to help your body fight all the harmful bacteria. If you stop your antibiotic early, the bacteria that have not yet been killed can restart an infection.

Can I save the antibiotic for the next time I am sick? 
No. Leftover antibiotics are not a complete dose, and they will not work to kill all your disease-causing bacteria. Taking partial doses can select for the bacteria that are resistant. In addition, your symptoms may not be caused by bacteria, so it is important to talk to your doctor before taking any antibiotics. If you do have another bacterial infection, acomplete dose of the appropriate antibiotic is needed to kill all the harmful bacteria.

What should women know before taking antibiotics?

  • Antibiotics often lead to a vaginal yeast infection. Because antibiotics kill the normal bacteria in the vagina, yeast no longer have competition for foodand grow rapidly. Yeast cells begin attacking tissues in the vagina, usually causing one or all of the following symptoms: itching, burning, pain during sex and vaginal discharge. If you think you have a yeast infection, consult a physician.

  • Antibiotics may reduce the efficacy of birth control pills. 

  • As with other medications, some antibiotics may be transmitted to a fetus, and some may cause harm. Therefore, you should never take antibiotics without your doctor's knowledge if you are pregnant or nursing. 

What is antibiotic resistance? 
Sometimes bacteria find a way to fight the antibiotic you are taking and your infection won't go away. Doctors call this antibiotic resistance. When resistance develops your doctor will need to prescribe a different antibiotic to fight your infection.

Why should I be concerned about resistant bacteria?
If your prescription does not work against a bacterial germ, your illness lasts longer, and you may have to make return office and pharmacy visits to find the right drug to kill the germ. For more serious infections, it is possible that you would need to be hospitalized or could even die if the infection could not be stopped. Also, while the resistant bacteria are still alive, you act as a carrier of these germs, and you could pass them to friends or family members.

What are some actions I can take to limit the development of antibiotic resistance?
A new class of antibiotic drugs is not expected to appear in the immediate future. If bacteria become resistant to all our current antibiotics, we won't have any other alternatives. Using antibiotics wisely will help preserve their effectiveness in the years ahead.

Here are some actions you can take to limit the development of antibiotic resistance—

  • Do not demand antibiotics from your physician. When given antibiotics, take them exactly as prescribed and complete the full course of treatment; do not hoard pills for later use or share leftover antibiotics, as decreased quality may compromise effectiveness. Wash your hands properly to reduce the chance of getting sick and spreading infection.  Wash fruits and vegetables thoroughly; avoid raw eggs and undercooked meat, especially in ground form. (The majority of food items which cause diseases are raw or undercooked foods of animal origin such as meat, milk, eggs, cheese, fish or shellfish.)

  • When protecting a sick person whose defenses are weakened, soaps and other products with antibacterial chemicals are helpful, but should be used according to established procedures and guidelines.

  • Read more: Unnecessary Deaths: The Human and Financial Costs of Hospital Infections by the Committee to Reduce Infection Deaths (RID).