This website has info about the max doses of some drugs, this info corresponds with info i have read on other medical sites. However the max dose is almost always 2x the max dose listed on the bottles. Aspirin bottles say not to take more than 6 tablets over 24 hours, that site say 6000mg (18.5 325mg tablets) is the max dose. Aleve (naproxen) bottles say 3 tablets a day, that site says about 6.
What is the difference? is the max dose on the bottle like the low/no risk dose, and the max on websites is the maximum dose any reasonable person should take, beyond which serious complications become common?
It’s been my experience that the OTC bottle warnings usually stipulate “…XX tablets in XX time, unless directed by a physician.”
The “maximum dosage” from the website or other medical references is more likely empirically derived, albeit with an additional safety factor included to allow for differences in body weight and metabolism. To give an actual “maximum safe dose” one would probably need to give more information (e.g., recommend X mg per Kg of body weight).
About ten years ago, I worked in a pharmacy and we often had to calculate the total dosage for various painkillers and have the pharmacist check with the doctor to make sure that the prescription was OK as written. The limits we used, if memory serves, were pretty close to the ones listed on your website.
It refers to the toxicity. At a small enough dose, anything is good for you (curare, arsenic, radiation) but a larger dose will induce a non-positive outcome (illness, disablement, death).
It varies quite a bit from drug to drug.
For Acetaminophen (“Tylenol” and such), even long term normal use can damage your liver. Increasing the dose for even a short term is Not A Good Thing.
For Ibuprofen (“Advil” and such), the OTC dose is lower than the prescription dose. So taking a larger dose is less risky but there are possible complications depending on your particular medical conditions, other drugs you are taking and so on. So guess what? You really need to see a doctor if you want to take more than the OTC dosage. What a surprise. Could be safe, could be fatal.
So it depends on the drug and but it also depends on you.