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A 22-year-old female asked:

are antibiotics targeted toward certain illnesses or do they generally fight off whatever infection is in your body? i am currently taking an antibiotic for a uti and caught a cold, wondering if this medicine will fight it off at all or only treat the uti

2 doctor answers2 doctors weighed in
Dr. Todd Mcniff
Internal Medicine 20 years experience
Antibiotics, : Antibiotics, when prescribed appropriately, are targeted to specific illnesses. They're actually targeted to specific bacteria that we know are responsible for certain illnesses. For example, most urinary tract infections are caused by a bacteria known as e. Coli, and we know that e. Coli is very sensitive to certain antibiotics. So when you suspect or know that someone has a uti, you would give them an antibiotic that is effective against e. Coli. That same antibiotic probably wouldn't work so well for a skin infection, which we know are typically caused by staph bacteria. If someone has a skin infection, they may be given keflex, minocycline, or other drugs that are effective at killing staph. Minocycline will probably do the trick for a skin infection caused by staph, but it may not do much for an e. Coli urinary tract infection. No antibiotic is going to treat a virus, which is what causes the typical cold. Sometimes cold symptoms are more than a viral illness, and could be representative of a bacterial bronchitis or pneumonia. And if that's the case, you'd want an antibiotic that not only kills the bugs that we know cause pneumonia, like strep. Pneumoniae, but also penetrates into the respiratory tract. All this being said, most antibiotics are wide spectrum enough to be multi-purpose, but that's a scary though. Think about it this way, if you always use a nuclear bomb against a cockroach, someday that's not going to kill the cockroach. And where does that leave you? The use of the most specific antibiotic for whatever bacterial infection is going on, typically leads to just as many cures, fewer side effects, and less emergence of resistant bacteria. We've only got so many antibiotics, and we're not developing new ones as quickly as we're burning through the old ones. Next time a doctor suggests that you don't need an antibiotic, realize that he'd say the same thing to his wife, husband, son or daughter.
Dr. John Kim
Dr. John Kim answered
Ophthalmology 22 years experience
Antibiotics : Antibiotics work against bacterial infection. They do not work against viral infection which your common cold is caused by. So, it is no suprise that you can get a common cold while on antibiotics.

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Last updated Oct 4, 2016

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