I have no idea about dea regulations and if you find evidence of such a policy you could bring it to the attention of the Head pharmacist. Other then that as long as you follow the hospitals policy I don't see why there would be a problem. A nurse could possibly divert the drugs with saline but that is not an issue you should worry about, at least ideally. It isn't a bad idea to brush up on the signs and symptoms of addiction in the workplace, though, and maybe keep it in the back of your mind when working with fellow employees if something seems abnormal. As long as the narcotics are witnessed to be properly wasted according to the hospital policy, I don't think there is any form of malpractice on your part and would not worry about it.