ELI5 Why isn’t more antibiotics injected rather than oral?

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Not really, because if you inject something it goes into your blood, and blood goes everywhere. But giving antibiotics orally is very much less invasive than IV. if treatments are not invasive, then patients are more likely to take them.


The injection is more complicated, you need some training to do it correctly, and there is also the risk of infection. Most antibiotics are taken at home by the one with the infection that likely has no medical training. Swallowing a pill is simpler. Injection yourself or having someone else do it is not simple, it requires training to do it in a safe way. The result is there are very few medical interventions that are done at home that require injection. If there is a requirement there is some training involved. So injected antibiotics are used in a hospital setting if the oral variant is not appropriate. There you have trained people that can handle it.


Because injections need to be performed by medical professionals and that would require people to make a LOT of trips to hospitals or GP’s and it’d put a huge strain on those facilities. Also, the more effort it takes to do something, the higher the odds people will quit doing it before it’s safe to quit. ​ Purely from a medical standpoint its a good idea. But it’s not practical in the real world


Probably be a bit less convenient if the treatment lasts for 5-7 days or longer and having to get that person into a setting to make the injection daily, or twice daily. Doable but rather impractical for most people. If there is a serious infection (like blood sepsis), then the patient will be hospitalized and IV antibiotics given.


That is not how antibiotics work. Well, at least not how all of them do. If you have a pneumonia (infection of the lungs) you will still get the antibiotics i.v. (intravenous) or p.o. (per os – oral) because the active substances go through the bloodstream to the bacteria. If you have an infection of the gastrointestinal system you will most likely receive antibiotics p.o., and if you are lucky and your type of bacteria is susceptible to non-absorbable antibiotics than you will get one of those. For example C.Difficile can be treated with Vancomycin which does not get absorbed from your intestines and works only inside the gastrointestinal tract. This will help you not get problems with the bacteria in your skin and mucosa causing mycosis (infections with fungus). To sum it up: it does not matter how you give the antibiotic (almost never, an exception I have mentioned), it will sadly almost every single time destroy the good bacteria reaching it through the bloodstream. ​ Side note: there are other options nowadays and we are trying to use local antibiotics. For pneumonia we can also do inhalative therapy. For urinary infections we have some antibiotics that get excreted in urin and for other types of incetions (skin, eyes, ears) we have drops or ointments.