ePrescribing in EU and Ireland: FHIR-Based Electronic Prescriptions

Executive Summary

Electronic prescribing (ePrescribing) transforms medication ordering from paper-based, error-prone processes to digital workflows with built-in safety checks, formulary integration, and cross-border interoperability. Ireland’s national ePrescribing rollout, combined with EU cross-border initiatives, enables Irish patients to fill prescriptions anywhere in Europe using FHIR-based standards.

This guide covers Ireland’s ePrescribing infrastructure, FHIR MedicationRequest/MedicationDispense resources, EU cross-border ePrescribing (eHDSI), drug database integration, and production .NET implementation patterns.

What You’ll Learn:

• Ireland’s ePrescribing programme (HSE)
• FHIR MedicationRequest resource structure
• Drug safety checks (interactions, allergies, contraindications)
• EU cross-border ePrescribing via eHDSI
• WHO ATC drug classification
• Irish Medicines Board (HPRA) integration
• Pharmacy dispensing workflow
• Production .NET code examples

Tech Stack: FHIR R4 | .NET 10 | WHO ATC | SNOMED CT | HSE ePrescribing | eHDSI

Traditional Paper Prescriptions

Pain Points:

1. Illegible Handwriting

   • 7,000+ deaths annually in US from medication errors
   • Pharmacists spend hours deciphering prescriptions
   • Common confusion: "mg" vs "mcg" (1000x difference!)

2. No Safety Checks

   • Doctor doesn’t see drug-drug interactions
   • No allergy alerts
   • No contraindication warnings
   • Dosing errors (pediatric especially dangerous)

3. Patient Burden

   • Must physically deliver prescription to pharmacy
   • Lost prescriptions = delay in treatment
   • Can’t fill prescription while traveling

4. Fraud & Abuse

   • Prescription forgery
   • Duplicate prescriptions
   • Controlled substance diversion

ePrescribing Benefits

✅ Safety:

• Real-time drug interaction alerts
• Allergy checking against patient record
• Dosing guidelines (especially pediatric)
• Formulary compliance

✅ Efficiency:

• No paper, no fax, no phone calls
• Prescription at pharmacy before patient arrives
• Electronic renewal requests
• Automatic refill reminders

✅ Clinical Decision Support:

• Cost-effective alternatives suggested
• Generic substitutions
• Prior authorization automation
• Therapeutic duplication alerts

✅ Patient Convenience:

• Choose any pharmacy
• Fill prescription anywhere in EU
• Track prescription status
• Medication history always available

HSE National ePrescribing System

Current Status (2025):

• Pilot in 15 acute hospitals
• Rollout to all public hospitals by 2026
• GP practices integration 2026-2027
• Community pharmacy connectivity 2025-2026

Technology Stack:

• FHIR R4-based
• Integration with IHI (Individual Health Identifier)
• Cloud-hosted (Azure Ireland region)
• Healthlink network for pharmacy connections

Key Components

1. Hospital Prescribing

• EMR integration (Cerner, Epic, InterSystems)
• Clinical decision support
• Discharge prescription generation

2. GP Prescribing

• GP practice software integration (Socrates, Healthone)
• Repeat prescription management
• GMS (General Medical Services) card integration

3. Pharmacy Dispensing

• Community pharmacy systems
• Hospital pharmacy systems
• Dispensing validation
• Stock management integration

4. Patient Portal

• View active prescriptions
• Request renewals
• Medication history
• Allergy management

Production-Ready C# Code

using Hl7.Fhir.Model;
using Hl7.Fhir.Rest;
using System.Collections.Generic;
using System.Threading.Tasks;

public class EPrescribingService
{
    private readonly FhirClient _fhirClient;
    private readonly IDrugInteractionService _drugChecker;
    private readonly IAllergyService _allergyService;

    public async Task<MedicationRequest> CreatePrescriptionAsync(
        string patientIHI,
        string practitionerId,
        MedicationData medication)
    {
        // 1. Build FHIR MedicationRequest
        var request = new MedicationRequest
        {
            Status = MedicationRequest.medicationrequestStatus.Active,
            Intent = MedicationRequest.medicationRequestIntent.Order,
            Priority = MedicationRequest.medicationRequestPriority.Routine,

            // Medication using WHO ATC
            Medication = new CodeableConcept
            {
                Coding = new List<Coding>
                {
                    new Coding
                    {
                        System = "http://www.whocc.no/atc",
                        Code = medication.AtcCode,
                        Display = medication.Name
                    }
                },
                Text = medication.Name
            },

            // Patient (Irish IHI)
            Subject = new ResourceReference($"Patient/{patientIHI}"),

            // Prescriber
            Requester = new ResourceReference($"Practitioner/{practitionerId}"),

            // Prescription date
            AuthoredOn = DateTimeOffset.Now.ToString("yyyy-MM-ddTHH:mm:sszzz"),

            // Dosage
            DosageInstruction = new List<Dosage>
            {
                new Dosage
                {
                    Sequence = 1,
                    Text = medication.DosageText,
                    Timing = new Timing
                    {
                        Repeat = new Timing.RepeatComponent
                        {
                            Frequency = medication.Frequency,
                            Period = 1,
                            PeriodUnit = Timing.UnitsOfTime.D
                        }
                    },
                    Route = new CodeableConcept
                    {
                        Coding = new List<Coding>
                        {
                            new Coding("http://snomed.info/sct", "26643006", "Oral")
                        }
                    },
                    DoseAndRate = new List<Dosage.DoseAndRateComponent>
                    {
                        new Dosage.DoseAndRateComponent
                        {
                            DoseQuantity = new Quantity
                            {
                                Value = medication.DoseValue,
                                Unit = medication.DoseUnit,
                                System = "http://unitsofmeasure.org",
                                Code = medication.DoseUnit
                            }
                        }
                    }
                }
            },

            // Dispense request
            DispenseRequest = new MedicationRequest.DispenseRequestComponent
            {
                ValidityPeriod = new Period
                {
                    Start = DateTimeOffset.Now.ToString("yyyy-MM-dd"),
                    End = DateTimeOffset.Now.AddMonths(6).ToString("yyyy-MM-dd")
                },
                NumberOfRepeatsAllowed = medication.RefillsAllowed,
                Quantity = new Quantity
                {
                    Value = medication.QuantityValue,
                    Unit = medication.QuantityUnit
                },
                ExpectedSupplyDuration = new Duration
                {
                    Value = 30,
                    Unit = "days",
                    System = "http://unitsofmeasure.org",
                    Code = "d"
                }
            },

            // Clinical reason
            ReasonCode = new List<CodeableConcept>
            {
                new CodeableConcept
                {
                    Coding = new List<Coding>
                    {
                        new Coding
                        {
                            System = "http://snomed.info/sct",
                            Code = medication.IndicationCode,
                            Display = medication.IndicationText
                        }
                    }
                }
            }
        };

        // 2. Run safety checks BEFORE creating
        await PerformSafetyChecks(request, patientIHI);

        // 3. Create on FHIR server
        var created = await _fhirClient.CreateAsync(request);

        // 4. Notify pharmacy
        await NotifyPharmacy(created);

        return created;
    }

    private async Task PerformSafetyChecks(MedicationRequest request, string patientIHI)
    {
        var errors = new List<string>();

        // Check 1: Allergies
        var allergies = await _allergyService.GetPatientAllergies(patientIHI);
        var drugAllergy = allergies.FirstOrDefault(a => 
            a.IsContraindicatedFor(request.Medication));
        
        if (drugAllergy != null)
        {
            errors.Add($"CRITICAL: Patient allergic to {drugAllergy.AllergenName}");
        }

        // Check 2: Drug interactions
        var currentMeds = await GetCurrentMedications(patientIHI);
        var interactions = await _drugChecker.CheckInteractions(
            request.Medication, currentMeds);

        var severeInteractions = interactions.Where(i => i.Severity == "severe");
        if (severeInteractions.Any())
        {
            errors.Add($"SEVERE INTERACTION: {string.Join(", ", severeInteractions.Select(i => i.Description))}");
        }

        // Check 3: Dosing appropriateness
        if (!IsDoseAppropriate(request))
        {
            errors.Add("Dose outside recommended range");
        }

        // Check 4: Duplicate therapy
        var duplicates = currentMeds.Where(m => 
            m.TherapeuticClass == request.Medication.TherapeuticClass);
        if (duplicates.Any())
        {
            errors.Add($"WARNING: Duplicate therapy with {string.Join(", ", duplicates.Select(d => d.Name))}");
        }

        if (errors.Any(e => e.StartsWith("CRITICAL")))
        {
            throw new PrescriptionSafetyException(string.Join("; ", errors));
        }
    }
}

Receiving Prescription at Pharmacy

Steps:

1. Prescription Arrival

   • Real-time notification via FHIR Subscription
   • Or: Patient presents with prescription ID
   • Pharmacist retrieves MedicationRequest from FHIR server

2. Verification

   • Validate prescriber credentials
   • Check prescription hasn’t been filled
   • Verify patient identity (IHI + photo ID)
   • Confirm medication in stock

3. Clinical Review

   • Pharmacist reviews dosing
   • Checks for interactions with OTC medications
   • Counsels patient on usage
   • Documents any concerns

4. Dispensing

   • Fill prescription
   • Label with instructions
   • Create MedicationDispense FHIR resource

MedicationDispense FHIR Resource

public class PharmacyService
{
    public async Task<MedicationDispense> DispensePrescription(
        string prescriptionId,
        string pharmacistId,
        string pharmacyId)
    {
        // 1. Get original prescription
        var prescription = await _fhirClient.ReadAsync<MedicationRequest>(
            $"MedicationRequest/{prescriptionId}");

        // 2. Create dispense record
        var dispense = new MedicationDispense
        {
            Status = MedicationDispense.MedicationDispenseStatusCodes.Completed,
            
            // Link to prescription
            AuthorizingPrescription = new List<ResourceReference>
            {
                new ResourceReference($"MedicationRequest/{prescriptionId}")
            },
            
            // Medication dispensed
            Medication = prescription.Medication,
            
            // Patient
            Subject = prescription.Subject,
            
            // Performers
            Performer = new List<MedicationDispense.PerformerComponent>
            {
                new MedicationDispense.PerformerComponent
                {
                    Actor = new ResourceReference($"Practitioner/{pharmacistId}"),
                    Function = new CodeableConcept(
                        "http://terminology.hl7.org/CodeSystem/medicationdispense-performer-function",
                        "finalchecker",
                        "Final Checker"
                    )
                }
            },
            
            // Location
            Location = new ResourceReference($"Location/{pharmacyId}"),
            
            // When dispensed
            WhenHandedOver = DateTimeOffset.Now.ToString("yyyy-MM-ddTHH:mm:sszzz"),
            
            // Quantity
            Quantity = prescription.DispenseRequest.Quantity,
            
            // Days supply
            DaysSupply = prescription.DispenseRequest.ExpectedSupplyDuration,
            
            // Dosage instructions
            DosageInstruction = prescription.DosageInstruction
        };

        // 3. Submit to FHIR server
        var created = await _fhirClient.CreateAsync(dispense);

        // 4. Mark prescription as filled
        await MarkPrescriptionFilled(prescriptionId);

        return created;
    }
}

Technical Implementation

Irish Patient in Barcelona Scenario:

Data Transformation

Ireland uses FHIR R4, some countries use CDA:

• Irish NCP converts FHIR → EU Patient Summary format
• Spanish NCP may convert to local format
• Round-trip: Local → EU format → Local

Key Challenge: Drug Coding

• Ireland: WHO ATC codes
• Spain: Local formulary codes
• Translation needed at NCP layer

Security & Privacy

Patient Consent Required:

• Explicit opt-in via MyHealth@EU portal
• Or: Consent at GP visit
• Logged in HSE IHI system

Audit Trail:

• Every access logged (GDPR Article 30)
• Patient can view access history
• Cross-border access tracked separately

Authentication:

• Pharmacist authenticated by local system
• NCP-to-NCP uses mutual TLS
• Patient identity verified with IHI + passport

FHIR Medication Resources

• FHIR MedicationRequest R4
• FHIR MedicationDispense R4
• FHIR Medication R4
• FHIR MedicationStatement R4

Drug Classification

• WHO ATC Classification
• DDD (Defined Daily Dose)
• SNOMED CT Pharmaceuticals
• RxNorm (US)

Irish Healthcare

• HSE ePrescribing Programme
• Irish Medicines Board (HPRA)
• Healthlink Ireland
• GMS (General Medical Services)

EU Standards

• eHDSI ePrescription
• MyHealth@EU Portal
• EU ePrescription Dataset

Drug Safety

• Drug Interaction Checker
• FDA Drug Safety Communications
• EMA Pharmacovigilance
• Irish National Medication Safety Programme

Implementation Guides

• US Core Medication Profile
• IHE Pharmacy
• Firely .NET SDK

1. HL7 v2: The Messaging Standard
2. HSE Digital Transformation
3. GDPR + FHIR Compliance
4. CDA Clinical Documents
5. EMR Modernization
6. HL7 v3 Overview
7. IPS in EU
8. FHIR Subscriptions

Electronic prescribing represents one of healthcare IT’s most impactful improvements—reducing medication errors, improving patient safety, and enabling cross-border care. Ireland’s national ePrescribing programme, built on FHIR standards, positions Irish healthcare for seamless EU integration while delivering immediate safety and efficiency benefits.