"Take two tablets every four to six hours, up to four times daily."
These are the standard dosing instructions we see on drugstore bottles of aspirin, acetominophen, and ibuprofen. "Take two [at the time]" is such a common instruction for medications that it's almost become a cultural joke. But if you go over to the drug manufacturer's site, or to a site like drugs.com, you'll find another story that may cause you to question the first. That story is the drug's activity curve.






