Medicine Database research materials?

This request is more about some research materials...

I want to build an application to control medicine dosage and to do this I think about making sample database with like 1000 medicines with info most importantly about a dosage (4 times a day, every 4 hours...) and composition.

Does anyone know about some webpage that could easily provide me with this kind of information? I think about webscrapping it with python. Or maybe somewhere there is already created sample database like this.

Also, I think about making feature about what elements in medicine composition can be dangerous together. Something like: That you can't take some 3 medicines together. Maybe someone know and could recommend some webpage, article, maybe algorithm that could provide me more knowledge about this subject.