A parasite is a type of germ that needs to live on or in another living being host. Antibiotics do not work against infections that are caused by viruses for example, the common cold or flu , or fungi for example, thrush in the mouth or vagina , or fungal infections of the skin. Microbes, Germs and Antibiotics discusses the different types of germs which can cause infections. Occasionally, a viral infection or minor bacterial infection develops into a more serious secondary bacterial infection.
In this case, antibiotics would be needed. There are various antibiotics available and they come in various different brand names. Antibiotics are usually grouped together based on how they work. Each type of antibiotic only works against certain types of bacteria or parasites. This is why different antibiotics are used to treat different types of infection. The main types of antibiotics include:. As well as the above main types of antibiotics, there are a number of other antibiotics that specialist doctors or hospital doctors may prescribe for more uncommon infections such as tuberculosis TB.
All my patients seem to know the rule about not drinking when you're on antibiotics - the troubl Some antibiotics work by killing germs bacteria or the parasite. This is often done by interfering with the structure of the cell wall of the bacterium or parasite. Some work by stopping bacteria or the parasite from multiplying. Antibiotics are normally only prescribed for more serious infections with germs bacterial and some parasitic infections.
Most common infections are caused by viruses, when an antibiotic will not be of use. Even if you have a mild bacterial infection, the immune system can clear most bacterial infections.
For example, antibiotics usually do little to speed up recovery from most ear, nose and throat infections that are caused by bacteria. So, do not be surprised if a doctor does not recommend an antibiotic for conditions caused by viruses or non-bacterial infections, or even for a mild bacterial infection.
However, you do need antibiotics if you have certain serious infections caused by bacteria, such as meningitis or pneumonia. In these situations, antibiotics are often life-saving. When you are ill, doctors are skilled at checking you over to rule out serious illness and to advise if an antibiotic is needed. Urine infections also commonly need antibiotics to prevent spread to the kidneys. Antibiotics can also be prescribed to treat acne - a less serious condition.
For acne, antibiotics can be taken by mouth or applied directly to the skin. The choice of antibiotic mainly depends on which infection you have and the germ bacterium or parasite your doctor thinks is causing your infection. This is because each antibiotic is effective only against certain bacteria and parasites. For example, if you have pneumonia , the doctor knows what kinds of bacteria typically cause most cases of pneumonia. He or she will choose the antibiotic that best combats those kinds of bacteria.
Even if you are pregnant or breastfeeding there are a number of antibiotics that are thought to be safe to take. It is important to take antibiotics in the correct way. If you do not, this may reduce how well they work. For example, some antibiotics need to be taken with food and others should be taken on an empty stomach. If you do not take your antibiotics in the right way it will affect how much of them get into your body their absorption and therefore they may not work as well. Results of these tests usually take a day or two and thus cannot guide the initial choice of antibiotic.
In such cases, doctors typically start treatment with an antibiotic that is effective against the bacteria most likely to be causing the infection. When test results are back, doctors change the antibiotic if needed. Antibiotics that are effective in the laboratory do not necessarily work in an infected person. The effectiveness of the treatment depends on. How well the drug is absorbed into the bloodstream for drugs taken by mouth Oral route Drugs are introduced into the body by several routes.
They may be Taken by mouth orally Given by injection into a vein intravenously, IV , into a muscle intramuscularly, IM , into the space How much of the drug reaches the sites of infection in the body see Drug Distribution Drug Distribution Drug distribution refers to the movement of a drug to and from the blood and various tissues of the body for example, fat, muscle, and brain tissue and the relative proportions of drug in How quickly the body eliminates the drug see Drug Elimination Drug Elimination Drug elimination is the removal of drugs from the body.
See also Introduction to Administration and Kinetics of Drugs. All drugs are eventually eliminated from the body. They may be eliminated Doctors also consider how hard it may be for people to take antibiotics for the entire time prescribed and complete the full course of treatment.
People may find it more difficult to complete treatment if the drug must be taken very often or only at specific times such as before meals, during meals, or after meals. Severe infections, particularly during the first days when the bacteria's susceptibility to antibiotics is not known. Infections caused by more than one type of bacteria if each type is susceptible to a different antibiotic. Bacteria, like all living organisms, change over time in response to environmental challenges.
Because of the widespread use and misuse of antibiotics, bacteria are constantly exposed to these drugs. Although many bacteria die when exposed to antibiotics, some develop resistance Antibiotic resistance Bacteria are microscopic, single-celled organisms.
For example, 50 years ago, Staphylococcus aureus a common cause of skin infections was very sensitive to penicillin. But over time, strains of this bacteria developed an enzyme able to break down penicillin, making the drug ineffective. Researchers responded by developing a form of penicillin that the enzyme could not break down, but after a few years, the bacteria adapted and became resistant to this modified penicillin.
Other bacteria have also developed resistance to antibiotics. Medical research continues to develop drugs to combat bacteria. But people can help prevent the development of resistance in bacteria by. Taking antibiotics only when necessary that is, people should take antibiotics only for infections caused by bacteria, not for those caused by viruses such as a cold or the flu. Not asking doctors to prescribe antibiotics for viral infections, such as the common cold or the flu. If a virus is causing the infection, taking antibiotics is useless and can contribute to the development of resistance in bacteria.
For severe bacterial infections, antibiotics are usually first given by injection Oral route Drugs are introduced into the body by several routes. When the infection is controlled, antibiotics can then be taken by mouth Oral route Drugs are introduced into the body by several routes. When doctors prescribe antibiotics for older people, they may prescribe a lower dose than usual because the kidneys tend to function less well as people age.
In such cases, the kidneys may not be able to eliminate antibiotics from the body as effectively, increasing the risk of side effects. See also Aging and Drugs Aging and Drugs Drugs, the most common medical intervention, are an important part of medical care for older people. Without drugs, many older people would function less well or die at an earlier age. What other drugs the person is taking because older people tend to take many drugs and drug interactions are a risk.
Whether the person has family members or caregivers who can help the person take the antibiotic as prescribed. Whether the person lives in a nursing home because different bacteria may cause infections in such situations. Antibiotics need to be taken until the infecting bacteria are eliminated from the body, which may be days after the symptoms disappear. Antibiotics are rarely given for fewer than 5 days. An exception is certain uncomplicated urinary tract infections Overview of Urinary Tract Infections UTIs In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present.
The tube that carries urine from the bladder out of the body urethra contains no bacteria Stopping treatment too soon can result in a return of the infection. A doctor, nurse, or pharmacist can explain how the prescribed antibiotic should be taken and what side effects it may have. Some antibiotics must be taken on an empty stomach. Others should be taken with food. Metronidazole Metronidazole and Tinidazole Metronidazole is an antibiotic used to treat pelvic, abdominal, soft-tissue, gum, and tooth infections and abscesses in the lungs or brain.
Also, some antibiotics can interact with other drugs that people may be taking, possibly reducing the effectiveness or increasing the side effects of the antibiotic or the other drugs.
Some antibiotics make the skin sensitive to sunlight Chemical photosensitivity Photosensitivity, sometimes referred to as a sun allergy, is an immune system reaction that is triggered by sunlight.
Accidentally taking 1 extra dose of your antibiotic is unlikely to cause you any serious harm. But it will increase your chances of getting side effects, such as pain in your stomach, diarrhoea, and feeling or being sick. If you accidentally take more than 1 extra dose of your antibiotic, are worried or you get severe side effects, speak to your GP or call NHS as soon as possible. As with any medicine, antibiotics can cause side effects. Most antibiotics do not cause problems if they're used properly and serious side effects are rare.
Some people may have an allergic reaction to antibiotics, especially penicillin and a type called cephalosporins. In very rare cases, this can lead to a serious allergic reaction anaphylaxis , which is a medical emergency. Read more about the side effects of antibiotics. Some antibiotics are not suitable for people with certain medical problems, or women who are pregnant or breastfeeding. Only ever take antibiotics prescribed for you — never "borrow" them from a friend or family member. 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. Sometimes, however, 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. Several types of modern antibiotics are available, and they are usually only available with a prescription in most countries. Topical antibiotics are available in over-the-counter OTC creams and ointments.
Some medical professionals have concerns that people are overusing antibiotics. They also believe that this overuse contributes toward the growing number of bacterial infections that are becoming resistant to antibacterial medications. 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 to Alexander Fleming, speaking in his Nobel Prize acceptance speech in , said:.
As the man who discovered the first antibiotic almost 70 years ago predicted, drug resistance is starting to become commonplace. Antibiotics are ineffective against viruses. A doctor prescribes antibiotics for the treatment of a bacterial infection.
It is not effective against viruses. Viruses cause most upper respiratory tract infections URTIs , such as the common cold and flu.
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