What is antibiotic

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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. Some antibiotics do not mix well with other medicines, such as the contraceptive pill and alcohol. Read the information leaflet that comes with your medicine carefully and discuss any concerns with your pharmacist or GP.

There are hundreds of different types of antibiotics, but most of them can be classified into 6 groups. Other antibiotics include chloramphenicol used for eye and ear infections , fusidic acid used for skin and eye infections , and nitrofurantoin and trimethoprim used for urinary tract infections.

You may not need to take antibiotics for some bacterial infections. For example, you might not need them for many sinus infections or some ear infections. Taking antibiotics when they're not needed won't help you, and they can have side effects. Your health care provider can decide the best treatment for you when you're sick.

Don't ask your provider to prescribe an antibiotic for you. Antibiotics do not work on viral infections. For example, you shouldn't take antibiotics for. The side effects of antibiotics range from minor to very severe. Some of the common side effects include. You should only take antibiotics when they are needed because they can cause side effects and can contribute to antibiotic resistance.

Antibiotic resistance happens when the bacteria change and become able to resist the effects of an antibiotic. This means that the bacteria continue to grow. The information on this site should not be used as a substitute for professional medical care or advice.

Most bacteria are harmless and even helpful to people, but some can cause infections, like strep throat. Antibiotics ONLY treat certain infections caused by bacteria , such as:. Viruses are germs different from bacteria. They cause infections, such as colds and flu. However, antibiotics do not treat infections caused by viruses.

Anytime antibiotics are used, they can cause side effects. Common side effects range from minor to very severe health problems and can include:. For more information on antibiotic resistance, visit Antibiotic Resistance Questions and Answers.