Definition
Electronic Prescribing (eRx)
Electronic prescribing (eRx) is the computer-based creation, transmission and management of prescriptions between prescribers, pharmacies and payers, replacing paper, fax and phone orders with standardized electronic messages.
1 min readReviewed September 14, 2026
Also known as: E-prescribing, ePrescribing, Electronic prescription, Electronic prescribing of controlled substances
Key facts
- Main message standard
- NCPDP SCRIPT
- Medicare Part D standards
- 42 CFR 423.160
- Controlled substances
- DEA electronic prescribing requirements, 21 CFR Part 1311
- Part D controlled substance mandate
- SUPPORT Act (2018), effective January 1, 2021
What is electronic prescribing?
With eRx, a prescriber selects a drug, strength, directions and quantity in an EHR or e-prescribing application, and the prescription travels electronically to the patient's chosen pharmacy. Structured data avoids illegible handwriting and transcription errors and lets the system run safety checks before sending.
E-prescribing is more than a new prescription message. The same networks carry renewal requests, change requests, cancellations and fill notifications, and they connect prescribers to formulary, benefit and medication history information from payers and pharmacy benefit managers.
How electronic prescribing works
A working e-prescribing setup combines several standards and rules:
- Messaging: prescribers and pharmacies exchange NCPDP SCRIPT transactions, and CMS adopts specific SCRIPT versions for Medicare Part D and periodically moves to newer ones.
- Drug identification: prescriptions can carry drug identifiers such as RxNorm codes and National Drug Codes (NDCs) alongside the directions.
- Benefit checks: formulary and benefit data and real-time prescription benefit tools show coverage and patient cost at the point of prescribing.
- Controlled substances: electronic prescribing of controlled substances (EPCS) requires identity proofing, two-factor authentication and audited or certified software under DEA rules.
- Monitoring: many states require, and the Medicare Promoting Interoperability Program rewards, checking a prescription drug monitoring program (PDMP) before prescribing opioids.
Why electronic prescribing matters
E-prescribing touches compliance, market access and analytics:
- Compliance: the SUPPORT Act requires most controlled substance prescriptions under Medicare Part D to be sent electronically, CMS enforces a compliance threshold with exceptions, and many states have their own EPCS mandates.
- Pharma market access: formulary and real-time benefit tools shape which product a prescriber picks at the moment of prescribing.
- Health IT: certification criteria and Promoting Interoperability measures push EHR developers to support current SCRIPT versions.
- Analytics: prescription transactions and pharmacy claims record the prescriber's NPI, which links prescribing activity to provider directories.