Well yeah you try but there are a lot of drugs out there and lot of complexities.  We study everything and they just study meds, they are much better at the nuances of dosing, interactions, renal dosing, contraindications etc.

Your ability to catch all of these small things goes down when you are forced to see 20-40 patients a day.

Maybe coz I'm relatively young (medically, at least) and have never had to take multiple drugs at the same time.  Still, I would have thought the doctors would also take into account what other drugs you're on before prescribing anything to you.  Is the pharmacist a second layer of validation, or do they have a more accurate history of your medications?