I am an RN JCAHO Coordinator. Joint Commission doesn't tell us how many days any mdv can hang around opened. It tells us to use safe, best practice. My common sense tells me this would include manufacturer's instructions. Therefore, #1. I would discard any medication after the expiration date whether it is open or not;#2. I would date, maybe time and certainly initial any mvd I opened; #3. I would follow my hospital's policy as long it was the safest best practice possible and if it isn't I would see that that policy got changed. You need to remember, JCAHO doesn't go around regulating how long each mdv of any given med can be used after opening. It tells us to do the right things right. Someone here (above) said "gee I can't tell if something is contaminated or not". Well, that's why we have Policies & Procedures, manufacturer's recommendations, the CDCP, because no one can "tell" if a solution is contaminated.