That is because it takes time to develop a drug that works, determine what the optimal dose is, compare the results against a placebo group to make sure the results are real, and to make sure that it does not have serious adverse effects (AE).

Mild AEs are what you see on drug commercials when they disclose that it may cause stomach pain, diarrhea , etc. Bad AEs can cause high chances of severe reactions like stroke, heart attack, or death. And part of the test process is look for AEs over a period of time to make sure that the drug is safe.

All that said, modern medicine is great and getting better all the time. BUT I would personally be wary of having my family use a medicine that was rushed and that did not go through the normal rigorous testing process. No chance of schools "requiring" this any time soon, especially in an election year.