Corresponding responsibility is perhaps one of the most commonly misunderstood and/or (unfortunately) unknown concepts found in DEA’s regulations.  And yet, enforcement actions against pharmacies are most frequently initiated when a pharmacist fails to exercise his/her corresponding responsibility.  I have had countless conversations with practicing pharmacists who are either unfamiliar with the concept of a “corresponding responsibility” or don’t understand how to apply it in their daily practice. The DEA’s regulations (21 C.F.R. § 1306.04) addressing corresponding responsibility state A prescription for a controlled substance to be effective must be issued for a legitimate medical purpose by an individual practitioner acting in the usual course of his professional practice. The responsibility for the proper prescribing and dispensing of controlled substances is upon the prescribing practitioner, but a corresponding responsibility rests with the pharmacist who fills the prescription. An order purporting to be a prescription issued not in the usual course of professional treatment or in legitimate and authorized research is not a prescription within the meaning and intent of section 309 of the Act (21 U.S.C. 829) and the person knowingly filling such a purported prescription, as well as the person issuing it, shall be subject to the penalties provided for violations of the provisions of law relating to controlled substances.