WRT to painkillers (and, really, any other medication), be very very careful about legal liability. Your heart is definitely in the right place, but people (and the organizations which employ them) have gotten sued when employer-dispensed painkillers and other over-the-counter pharmaceuticals go wrong.
It's one thing to provide, like, a cup of hot tea or a headache compress or a quiet room with dim lighting where they can relax a bit to get rid of the headache. But most employers (and, by extension, the agents of these employers) should not dispense even the safest over-the-counter drugs except under very limited circumstances. (One way to protect yourself from liability is to sell it through a vending machine: that way the employee is paying for the dose and taking it entirely of their own volition, rather than being "issued" a pill by management. From a legal perspective, these are completely different things.)