[Symmetry]

So, what do you think would be the costs and benefits of waiting to approve a drug until we fully understood how produced it's intended effects? Clearly waiting until we understood every possible interaction for a drug would prevent any sort of mistake, but I'm not aware that we understand any drug in that detail. I hope you wouldn't suggest we abandon antibiotics because theres a chance that any given person taking one for the first time might have a unique allergic reaction.

My best guess on the numbers is that waiting to understand all drugs mechanisms beyond existing testing would, over the course of the FDA's history, have saved dozens of lives at the cost of failing to save millions.