Are small people seriously over-medicated? Big people under-medicated?

[Xithras]

5. The problem is that you may also double side effects.

Theoretically speaking, let's say that you have a drug that requires a 10mg dose to save heart function in a 140lb person, but that the medicine can cause liver damage if taken at higher doses. In order to save the same heart function in a 280lb person, the doctor would need to double the dosage to 20mg, but doing that he would push the drug well beyond its safe limits and start harming the liver.

Should he double the dosage?

This exact scenario actually exists for countless medications that are prescribed to us every day, and it's one of the many reasons that doctors try to convince their patients to lose weight. It's no secret that medications are less effective in overweight people, or that overweight people suffer more severe side effects from those medications if the dosages are increased to accommodate their weight.