Closed Loop Medicine Supply (CLMS) uses barcode scanning technology and digital systems to track medications from ordering through to dispensing and stock management creating real-time visibility of medicines across an NHS trust.
It refers to digital systems that capture and share data in real-time throughout the medicines supply chain. This includes monitoring medication ordering, dispensing, stock levels, expiration dates, and location, ensuring appropriate record keeping at each stage.
CLMS applies Scan4Safety principles – particularly product identification and location tracking – to medicines management workflows.
How Closed Loop Medicines Supply works
CLMS typically includes several interconnected processes:
Electronic ordering
- Wards electronically order medications through stock management systems
- Orders integrate with pharmacy dispensing systems and remove manual processes
- Barcode scanning eliminates manual processes
Dispensing with verification
- Pharmacy teams scan medications during dispensing
- Systems verify correct selection against the order
- Labels are automatically generated with patient, medication, and location details
Stock management
- Automated Drug Cabinets (ADCs) and robots track stock levels in real-time
- Minimum stock levels trigger automatic reordering
- Expiration dates are monitored with automated alerts
- Data is available in real time to allow for more efficient workflows for enacting drug recalls, stock identification and analysis of trends in drug usage.
Supply chain integration
- Incoming stock is scanned on receipt
- Barcodes link to supplier data and batch information
- Integration with pharmacy robots for automated dispensing
- Real-time visibility across the entire supply chain
How this applies Scan4Safety principles
CLMS relies on core Scan4Safety standards and technology:
- GS1 GTIN: Global Trade Item Numbers on medication packaging
- GS1 GLN: Global Location Numbers identifying specific locations (wards, cabinets, storage areas)
- Barcode scanning: Throughout the supply chain from receipt to dispensing
- Digital integration: Connecting pharmacy systems, stock management, EPR, and procurement
- Standards compliance: Meeting NHS standards including SCCI0052 (dm+d) and DAPB0108
Benefits of Closed Loop Medicines Supply
CLMS transforms medicines ordering, dispensing, and stock management through digital automation and real-time data capture. NHS trusts implementing CLMS report significant improvements across safety, efficiency, and operational workflow that support better patient outcomes and more effective pharmacy services.
- Dramatic reduction in dispensing errors: CLMS technology delivers measurable safety improvements through automated processes that reduce human error. Liverpool University Hospitals NHS Foundation Trust reported a 90% reduction in internal dispensing errors after implementing their closed-loop medicine supply system. The technology automatically generates labels and where automated drug cabinets are used, visual guidance systems ensure pharmacists select the correct medications, eliminating many opportunities for error in the dispensing process.
- Enhanced workflow and stock management: Digital ordering systems eliminate the problems associated with paper-based processes, which were prone to being misplaced or duplicated, causing delays and medication wastage. CLMS enables electronic ordering that flows seamlessly from wards to pharmacy dispensaries. In some cases this allows pharmacists to manage inpatient work earlier in the day and focus on discharge prescriptions during afternoon periods. This optimised workflow ensures patients receive their medications on time, reducing missed doses and improving care continuity.
- Improved inventory control and recall management: CLMS provides real-time stock monitoring and automated replenishment systems that maintain optimal inventory levels whilst reducing waste from expired or obsolete medications. During medication recalls, digital systems eliminate the need for manual stock checks across entire hospital sites, enabling rapid identification and removal of affected products.
You can also view our CLMS case studies to read real examples of how CLMS is being used by NHS trusts.
CLMS Implementation considerations
Below are some specific considerations for implementing a CLMS system.
You can also read some examples of implementation approaches used by NHS trusts in our CLMS case studies.
Implementing CLMM requires understanding how digital systems, clinical processes, and staff workflows integrate across the entire patient medication journey. We’ve developed detailed service blueprints that visualise CLMM processes at two different levels of automation – from intermediate implementation through to advanced systems incorporating automated drug cabinets.
Getting started with CLMS
Implementing CLMS involves several key steps:
- Map current processes: Understand your existing ordering, dispensing, and stock management workflows
- Assess system capabilities: Review integration options between your EPR, pharmacy, and stock management systems
- Engage pharmacy teams: Work closely with pharmacy leadership and staff to design optimised workflows
- Consider automation level: Decide whether to implement basic electronic systems or invest in Automated Drug Cabinets (ADCs) and robots
- Plan for integration: Budget time and resources for technical integration work
- Pilot strategically: Start with a defined scope (e.g., one ward type or medication category) to demonstrate benefits
- Scale with support: Roll out systematically with strong technical and change management support
Implementation approaches
Trusts implement CLMS at different levels based on digital maturity:
Basic CLMS
- Electronic ordering from wards to pharmacy
- Barcode scanning during dispensing
- Basic stock level tracking
- Suitable for trusts beginning digital medicines transformation
Intermediate CLMS
- Automated stock management systems
- Integration between ward ordering and pharmacy systems
- Barcode-enabled stock audits
- Expiration date monitoring
- Suitable for trusts with established electronic systems
Advanced CLMS
- Automated Drug Cabinets on wards
- Pharmacy robots for automated dispensing
- Real-time stock level monitoring and automatic reordering
- Full integration across prescribing, dispensing, and supply
- Suitable for trusts with advanced digital infrastructure
Implementation considerations
System integration
CLMS requires integration across multiple systems:
- Electronic prescribing and patient records
- Pharmacy dispensing systems
- Stock management platforms
- Procurement systems
- Automated Drug Cabinets
- Pharmacy robots
Many trusts report that system interoperability – particularly between EPR and pharmacy systems – remains a challenge requiring technical expertise and vendor cooperation.
Barcode quality and coverage
Not all medications arrive with scannable barcodes. Challenges include:
- Small packaging without adequate barcode space
- Damaged barcodes
- Medications requiring re-packaging
- Controlled drugs with specific labelling requirements
Solutions: Pharmacy barcode printers, supplier engagement to improve barcode quality, and processes for handling exceptions.
Drug catalogue maintenance
CLMS requires maintained drug catalogues mapping barcodes to the dm+d standard. This requires:
- Dedicated pharmacy technician time
- Processes for adding new medications
- Quality assurance to ensure accuracy
- Regular updates as products change
Trusts who have implemented CLMS emphasise the importance of including ongoing maintenance resources in business cases.
Staffing and training
Successful CLMS implementation requires:
- Technical staff to maintain systems and manage integrations
- Pharmacy staff trained in new workflows
- Ward staff confident in electronic ordering
- Clear escalation processes for system issues
Closed Loop Medicines Supply and Scan4Safety
Trusts with Scan4Safety implementation have key advantages for CLMS:
- Established GS1 barcode standards
- Scanning infrastructure and devices
- Staff familiarity with scanning workflows
- Technical expertise in barcode integration
- Supplier relationships for barcode quality
CLMS extends Scan4Safety principles into medicines supply chain management – creating safer, more efficient processes that benefit patients, pharmacy teams, and ward staff.
Closed Loop Medicines Supply case studies
The case studies below provide some real world examples of how NHS trusts have been implementing and using CLMA.
Non-urgent advice: The Royal Cornwall Hospitals NHS Trust (RCHT) | approximately 750 beds across three sites | Acute Secondary NHS Trust
Royal Cornwall Hospitals NHS Trust has implemented CLMS as part of their stock inventory management system which integrates with their electronic stock control programme.
The system produces paper drug orders with barcodes containing patient name, drug name, and location for the dispensary. This removes the need to re-type information from the prescribing system to the supply system. Automated electronic drug cabinets are in place on selected wards, enabling closed-loop supply of stock medication. Electronic orders are triggered when minimum stock levels are reached, with messages sent directly to the pharmacy robot for processing.
Benefits include reductions in dispensing errors and optimised workflow for ward stock management.
Non-urgent advice: Liverpool University Hospitals NHS Foundation Trust | approximately 850 beds | Acute Secondary NHS Trust
Liverpool University Hospitals NHS Foundation Trust implemented a closed-loop medicine supply system linked to the pharmacy dispensing system.
When the medication is prescribed a label is generated automatically. This process is used for controlled drugs (CDs) where the order is sent electronically from the ward to the Omnicell. Each ward has an individual ward stock list, and the authorised person sends the order electronically to the Omnicell in the pharmacy department. The system automatically generates the label, and the medication is dispensed from the cabinet, checked and released to the ward. The automated Omnicell cabinet highlights to the dispenser the required medication using a flashing light that automatically selects the cabinet that contains the required medication.
Since adopting this technology, the internal dispensing error rate has decreased by 90%. Improved workflow means inpatient work is sent via the system to the dispensary earlier in the day, allowing focus on discharge prescriptions in the afternoon. This has led to a reduction in the number of missed doses as patients receive medication on time.