Well, legally, CII's (any RX really) are only supposed to be filled for a legitimate medical purpose. If you *know* that the prescription is not for a legitimate medical use, then you have the duty not to dispense it. However, these situations where you *know* are going to be exceedingly rare. Most of the time, its just a vague suspicion. Your best bet, if you have legitimate questions about an RX is calling the doctor. Then document what you are told. There is usually no reason to doubt the doctor, unless you are dealing with a questionable FL doctor, or if the dosing is very questionable or the RX's are being written to frequently (ie the doctor is giving the pt a new RX every week for a month's supply.) Ultimately, its your call, if you do not feel comfortable filling the prescription, than give it back to the patient (when I have done this, I tell the patient-dosing is too high, to frequent refillls, etc.)