Should this young tennis player and John McEnroe take the same quantity of over-the-counter medications? (Source)

Should this 12-year-old tennis player and John McEnroe take the same dosage of over-the-counter medications? (Source)

Something about this seems goofy to me. This is one of those days when I’m writing about something I know almost nothing about but have wondered about for a very long time. Over-the-counter medications typically have dosing directions that read something like this example:

Adults and children 12 years of age and older:  Take 2 tablets every 6 hours as needed. Do not take more than 8 tablets in 24 hours.

Who came up with that? Why would an average 96-pound child of twelve years of age need the same strength medication as an adult who weighs 192 pounds or 288 pounds, two or three times the weight of a 12-year-old child? Does that make any sense? Not to me.

And not that I want higher doses myself. It’s the logic of those directions that defy my person-on-the-street understanding. I weigh about twice as much as a 96-pound 12-year-old child. How can a fixed amount of medication accomplish as much in a 200-pound person as it does in a 100-pound person? In a 300-pound person?

After several attempts to find an answer online, I gave up.

If any of you can cite a documented explanation for this logic puzzle for me in the comments below, I’d appreciate it. Surely, some of you can shed light on this. Does it make sense to you?