I’m assuming it has to do with making sure you get any straggler bacteria, but wouldn’t taking all the pills at once shock and awe the little buggers and force them to surrender?
In: Biology
Most antibiotics don’t kill bacteria, they prevent them from multiplying. This gives your body a chance to kill them off without them constantly growing back.
You need to maintain a certain amount of the antibiotic in your bloodstream to prevent them from multiplying. Your body is constantly eliminating the antibiotic through the liver and kidneys.
So you need a consistent dose over time to maintain enough in the blood.
If you were held at the bottom of a 8′ pool for 5 minutes you’d drown. If you were held at the bottom of a 40′ pool for a minute you could just hold your breath and resurface.
Sometimes a bit of shock is OK, but have to endure a harsh environment for a long period is much harder.
Essentially you need to have a certain safe concentration of the drug in your body for a certain amount of time for it to do its job. Some antibiotics directly kill bacteria and some just stop them from making baby bacteria but either way they don’t work instantly and take a little time to do their job.
ELI5+TLDR: regularly scheduled doses of an antibiotic, timed according to how the body metabolizes it, over a period of days, are necessary to clear/suppress/eliminate the bacterial infection.
ELI25: because of how bacteria grow as it relates to when they are susceptible to antibiotics, a one time/shock+awe approach does not work.
Because drugs are just poisons in smaller dosages. Take too much at once and it become a poison again
I’m an infectious diseases pharmacist, so antibiotics and how they work is pretty much my bread and butter. There are actually lots of antibiotics that you can take just once a day, but usually the ones that you take multiple times a day tend to be ones, like beta lactams, that are time dependent rather than concentration dependent in their killing. Those are two broad categories of how antibiotics work, and for the multiple times a day ones, it’s about keeping a minimum level in the blood over a longer period of time, and adding more doesn’t actually kill more; above a certain level it doesn’t make a difference. There are actually certain antibiotics where we’ve moved from multiple times a day dosing to once a day dosing (aminoglycosides) but that was possible only because aminoglycosides are concentration dependent and therefore the higher doses can actually “shock and awe” as you put it and dosing that way actually lowers the toxicity that you see with aminoglycosides.
There are time dependent antibiotics that are dosed just once a day but those tend to have longer half lives, or are slower to leave the body so you don’t have to keep replenishing to keep it above that minimal level (ceftriaxone and ertapenem come to mind)
So if the abx is dosed multiple times a day, it’s a mix of, it’s probably time dependent killing and is processed by the body quickly(usually by the kidneys), and taking it all at once or just all doses just once a day doesn’t keep enough of it in your body long enough to kill the bacteria and you’ll have to go through another course.
Toxicity is secondary and not most of what is driving dosing decisions. Though if you try to take all your cephalexin at once I imagine the stomach upset would not be fun.
in terms of the actual question:
It would but it wouldn’t work that way.
the antibiotics are ALREADY in essence doing that, but there is always some bacteria or cells etc. that either are more resistant/ “hidden” etc that won’t be able to be hit by the bacteria at the same time.
This is why the timeframe is important, because you need the antibiotics to be there in your body doing the “shock and awe” for a long enough
Time for it to work and kill them all off.
Essentially it’s kind of like boiling water: you are instantly killing the stuff in the water sure but it takes time for the heat to get all of the water to boil instead of just the stuff closer to the heat source.
There are absolutely antibiotics that work like this. Super strong. Super big. And the side effects are horrid. Lots of medicine is about the trade-offs between benefit and risk. In general, the slower and longer ones are the right choice.
All medications have a therapeutic range and for it to work the amount in your body needs to be within that range.
Think of a graph with a straight line at zero. That’s how much antibiotics you have in your system before you start.
If you take antibiotics now, the level will rise above zero. Soon after we do though, our body starts to remove it, usually due to the liver, and the level starts dropping again.
Above zero is another line called the therapeutic level. This is the amount of antibiotics you need in your body to work properly. If the amount ever falls below this level it won’t work well if at all.
Then there is another line above that, called the toxic level. If the amount in your body goes over this line then the antibiotics will start to cause damage to your body instead of helping.
Between those two lines is the therapeutic range. That’s the range we want the level to have the best effect. Too low and it stops working. Too high and it causes damage.
So we have this line on our graph that jumps up every time we take our medication, and then slowly starts to drop off again. This is why sometimes we’ll take two tablets on the first day and then one every day after that. Two tablets bumps us right into the middle of our therapeutic range and one more every day replaces what we eliminate before we drop out the bottom of the range.
Understanding this, we can see that if we take a whole week’s worth of medication all at once we put ourselves really high into the toxic range and harm ourselves instead of just killing the bacteria we’re targeting.
Antibiotics work by creating an environment in your body that is unfriendly to specific kinds of bacteria. They then keep the environment unfriendly to bacteria until the bacteria that is dangerous to you has their population reduced below a point where they can reproduce and harm you.
Even once the antibiotics are there it takes time for the bacteria to die, for your immune system to attack the bacteria and the population to be reduced to the point that the bacteria will be effectively extinct inside your body instead of being reduced a lot, then recovering the population with more resistance to the antibiotics.
There’s another problem too: Antibiotics aren’t always super gentle on the body. While not toxic if you take them as prescribed and your body only has to deal with a normal dosage you might poison yourself by taking a large amount at once.
Latest Answers