Eli5: if you get a bigger dose of a drug or a substance, does this mean that the drug becomes stronger or more long lasting?


Also, how come low doses of certain substances (medicinal stuff) are better than high doses ? aren’t higher doses more effective?

In: Chemistry

These are very good questions, and the answer is basically “it’s really complicated.” There’s an entire field of science (pharmacology) just devoted to studying this!

With **most** drugs, they display what’s called “first-order kinetics.” This is a very fancy way of saying that a certain *percent* of the drug in your blood gets taken out by your liver/kidneys per a certain amount of time, *regardless of what dose you took*.

For example, for a drug with a “half-life” of one hour, if you take 100mg, after one hour you will have 50mg in your blood. After two hours, you will have 25mg…and so on. If you start by taking 50mg, after one hour you will have 25 mg in your blood, and after two hours you will have 12.5 mg. So taking a higher dose will give you a stronger effect, but it might also make it last longer!

Most real drugs are a bit more complicated than this, but this is the general idea.

This question is way to generic and open ended. Taking more of something isn’t always bed, and most every medication is dangerous when taken in too high doses. TYPICALLY (but not always), a dose is prescribed to maintain the effective concentration in the body. Your needed concentration can also change based on the reason you are taken the medication.