Antibiotics are medicines that kill or stop the growth of certain types of bacteria, such as those that cause infections like strep throat and urinary tract infections. They can also be used to prevent infection before surgery or after an injury that might get infected.
Bacteria that survive antibiotic treatment may become resistant to the drugs. When this happens, the drug doesn’t work as well — or it may not work at all. Drug resistance is one of the world’s most urgent health problems. It develops when people take antibiotics when they don’t need them, or when they use them incorrectly. This includes taking antibiotics for viral illnesses like colds and flu, as well as using them to treat mild bacterial infections that would go away on their own.
There are many different kinds of antibiotics. The ones your doctor prescribes will depend on the type and severity of your infection. These medicines can be taken by mouth (as pills, liquids, or tablets), put on the skin as a cream or spray, or given through a vein (intravenously, or IV). Some antibiotics are used to treat only certain types of infections. Others, such as penicillins, are broad-spectrum and can be used to treat a range of infections. Others, such as quinolones and aminoglycosides, are narrow-spectrum and target just a few types of bacteria.
It can take up to 14 days for antibiotics to fully work. During this time, you should continue to take the medication as prescribed by your doctor. If you miss a dose, take it as soon as you remember. If you don’t, it may not be effective against your infection and your symptoms might return.