What to know about antibiotics
Last updatedWed 25 Jul 2018
By Christian Nordqvist
Reviewed by Philip Gregory, PharmD, MS
Table of contents
Antibiotics, also known as antibacterials, are medications that destroy or slow down the growth of bacteria.
They include a range of powerful drugs and are used to treat diseases caused by bacteria.
Antibiotics cannot treat viral infections, such as cold, flu, and most coughs.
This article will explain what antibiotics are, how they work, any potential side effects, and antibiotic resistance.
Fast facts on antibioticsAlexander Fleming discovered penicillin, the first natural antibiotic, in 1928.Antibiotics cannot fight viral infections.Fleming predicted the rise of antibiotic resistance.Antibiotics either kill or slow the growth of bacteria.Side effects can include diarrhea, an upset stomach, and nausea.
What are antibiotics?
Antibiotics are a commonly prescribed type of medication that combat bacteria.
Antibiotics are powerful medicines that fight certain infections and can save lives when used properly. They either stop bacteria from reproducing or destroy them.
Before bacteria can multiply and cause symptoms, the immune system can typically kill them. White blood cells (WBCs) attack harmful bacteria and, even if symptoms do occur, the immune system can usually cope and fight off the infection.
There are occasions, however, when the number of harmful bacteria is excessive, and the immune system cannot fight them all. Antibiotics are useful in this scenario.
The first antibiotic was penicillin. Penicillin-based antibiotics, such as ampicillin, amoxicillin, and penicillin G, are still available to treat a variety of infections and have been around for a long time.
There are several types of modern antibiotics, and they are usually only available with a prescription in most countries. Topical antibiotics are available in over-the-counter creams and ointments (OTC).
Resistance
There is concern that antibiotics are being overused, and that this overuse contributes toward the growing number of bacterial infections that are becoming resistant to antibacterial medications.
According to the Centers for Disease Control (CDC), outpatient antibiotic overuse is a particular problem. Antibiotic use appears to be higher in some regions, such as the Southeast.
Use of carbapenems, a major class of last-line antibiotics, increased significantly from 2007 to 2010.
Alexander Fleming, speaking in his Nobel Prize acceptance speech in 1945, said:
"Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug, make them resistant."
As predicted almost 70 years ago by the man who discovered the first antibiotic, drug resistance is starting to become commonplace.
How do antibiotics work?
There are different types of antibiotic, which work in one of two ways:
A bactericidal antibiotic, such as penicillin, kills the bacteria. These drugs usually interfere with either the formation of the bacterial cell wall or its cell contents.A bacteriostatic stops bacteria from multiplying.
Antibiotic resistance: What you need to know
Click here to learn more about bacterial antibiotic resistance.
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Uses
Antibiotics are not effectives against viruses.
A doctor prescribes antibiotics for the treatment of a bacterial infection. It is not effective against viruses.
If you have an infection, it is important to know whether it is bacterial or viral.
Viruses cause most upper respiratory tract infections, such as the common cold and flu. Antibiotics do not work against these viruses.
If people overuse antibiotics or use them incorrectly, there is a risk that the bacteria will become resistant. This means that the antibiotic becomes less effective against that type of bacterium, as the bacterium has been able to improve its defenses.
A doctor can prescribe a broad-spectrum antibiotic to treat a wide range of infections. A narrow-spectrum antibiotic is only effective against a few types of bacteria. Some antibiotics attack aerobic bacteria, while others work against anaerobic bacteria. Aerobic bacteria need oxygen and anaerobic bacteria do not.
In some cases, antibiotics may be given to prevent rather than treat an infection, as might be the case before surgery. This is called 'prophylactic' use of antibiotics. People commonly use these antibiotics before bowel and orthopedic surgery.
