Utilizing electronic prescriptions (eRx), ETASU enforcement for a drug associated with a REMS may be performed at a more natural point in prescription processing. By incorporating an encrypted REMS Dispense Authorization (RDA) into eRxs, an eRx router may validate various elements of the eRx against encrypted data elements and thereby verify that any ETASUs required by a REMS for a prescribed drug have been complied with. As a result, only validated eRx are passed from the eRx router to pharmacies for dispensing, reducing manual intervention to confirm compliance. Information necessary to perform validation may be communicated to the eRx router by a Trusted Central RDA Authority (TCRA), and may include decryption keys, prescriber authorization data, and appropriate validation check algorithms.