Morphine Milligram Equivalent (MME) Calculator
Module A: Introduction & Importance of MME Calculation
Morphine Milligram Equivalents (MME) represent a standardized method for comparing the potency of various opioids relative to morphine. This calculation is critical in clinical settings for several reasons:
- Patient Safety: Helps prevent opioid overdoses by standardizing dosage comparisons across different opioid medications
- Clinical Decision Making: Enables healthcare providers to make informed decisions about opioid prescribing and tapering
- Regulatory Compliance: Many states require MME calculation for opioid prescriptions exceeding certain thresholds
- Risk Assessment: Identifies patients at higher risk for opioid-related adverse events based on their total daily MME
The CDC guidelines recommend that clinicians should use caution when prescribing opioids at any dosage, carefully reassess evidence of individual benefits and risks when increasing dosage to ≥50 MME/day, and avoid increasing dosage to ≥90 MME/day or carefully justify a decision to titrate dosage to ≥90 MME/day.
Module B: How to Use This MME Calculator
Follow these step-by-step instructions to accurately calculate MME:
- Select the Opioid Medication: Choose the specific opioid from the dropdown menu. Our calculator includes all commonly prescribed opioids.
- Enter the Dosage: Input the exact dosage in milligrams (mg) as prescribed. For combination medications (like hydrocodone/acetaminophen), enter only the opioid component.
- Specify Frequency: Indicate how many times per day the medication is taken. For extended-release formulations, enter “1” if taken once daily.
- Select Administration Route: Choose the route of administration (oral, IV, transdermal, etc.). This affects the conversion factor for some medications.
- Calculate: Click the “Calculate MME” button to generate results. The calculator will display:
- Total daily MME
- CDC risk category
- Visual representation of risk levels
- Interpret Results: Review the calculated MME and associated risk category to inform clinical decisions.
Important Notes:
- For transdermal fentanyl, enter the patch strength in mcg/hour and frequency as “1” (since patches are typically changed every 72 hours)
- For methadone, conversion factors vary by dose (our calculator uses the standard 4:1 ratio for doses <40mg/day and 8:1 for higher doses)
- Always verify calculations with clinical judgment and patient-specific factors
Module C: MME Formula & Methodology
The MME calculation follows this fundamental formula:
Total Daily MME = (Dosage per administration × Conversion Factor) × Frequency per day
Each opioid has a specific conversion factor that represents its potency relative to morphine. Below are the standard conversion factors used in our calculator:
| Opioid | Oral Conversion Factor | Parenteral Conversion Factor | Notes |
|---|---|---|---|
| Morphine | 1 | 3 | Reference standard |
| Oxycodone | 1.5 | – | – |
| Hydrocodone | 1 | – | – |
| Fentanyl (transdermal) | 2.4 (mcg/hour = mg/day) | – | 25 mcg/hour = 60 mg/day MME |
| Hydromorphone | 4 | 20 | – |
| Oxymorphone | 3 | 10 | – |
| Methadone | Varies (4:1 for <40mg, 8:1 for ≥40mg) | Varies | Complex pharmacokinetics |
| Codeine | 0.15 | 0.5 | Weak opioid |
| Tramadol | 0.1 | – | Atypical opioid |
Methodology Notes:
- Our calculator uses the most current CDC conversion factors as of 2023
- For medications with multiple routes, the calculator automatically adjusts based on the selected administration route
- Transdermal fentanyl calculations account for the 72-hour wear time in the daily MME calculation
- Methadone conversions use a bifurcated approach based on daily dose thresholds
- All calculations are rounded to the nearest whole number for clinical practicality
For complete methodological details, refer to the CDC’s official MME calculation guide.
Module D: Real-World Case Studies
Case Study 1: Post-Surgical Pain Management
Patient: 45-year-old male, 72kg, post-ACL reconstruction
Prescription: Oxycodone 5mg every 4-6 hours as needed for pain
Actual Usage: Patient takes 5mg every 6 hours (4x daily)
Calculation:
5mg × 1.5 (conversion factor) × 4 = 30 MME/day
Clinical Consideration: This falls in the CDC’s “caution” range (20-49 MME/day). The surgical team decided to:
- Add ibuprofen 600mg every 8 hours for synergistic effect
- Limit oxycodone to 3 days post-op with clear tapering instructions
- Schedule follow-up at 1 week to assess pain control needs
Case Study 2: Chronic Pain Management
Patient: 62-year-old female, 68kg, with chronic back pain and osteoarthritis
Current Medications:
– Hydromorphone ER 8mg twice daily
– Hydromorphone IR 2mg every 4 hours as needed (average 3x daily)
Calculation:
Extended-release: 8mg × 4 × 2 = 64 MME/day
Immediate-release: 2mg × 4 × 3 = 24 MME/day
Total: 88 MME/day
Clinical Consideration: This approaches the CDC’s 90 MME/day threshold requiring special justification. The pain specialist:
- Added physical therapy and cognitive behavioral therapy
- Reduced ER hydromorphone to 6mg twice daily (48 MME)
- Kept IR dose same but limited to 2x daily (16 MME)
- New Total: 64 MME/day (below threshold)
- Scheduled monthly follow-ups to monitor pain control and functional improvement
Case Study 3: Opioid Rotation for Cancer Pain
Patient: 58-year-old male, 82kg, with metastatic prostate cancer and bone pain
Current Medication: Oxycodone IR 15mg every 4 hours (6x daily) with inadequate pain control
Current MME:
15mg × 1.5 × 6 = 135 MME/day
Decision: Rotate to methadone for better pain control and reduced side effects
Conversion Calculation:
135 MME × 0.5 (conservative rotation ratio) = 67.5 MME target
Using 8:1 conversion for methadone: 67.5 ÷ 8 ≈ 8.4mg
Prescription: Methadone 5mg every 8 hours (15mg/day)
Outcome:
- Pain control improved from 7/10 to 3/10
- Reduced sedation and nausea compared to oxycodone
- MME reduced to 60 MME/day (5mg × 8 × 1.5)
- Patient able to participate in physical therapy
Module E: MME Data & Statistics
The opioid crisis remains a significant public health challenge in the United States. Understanding MME distributions and trends is crucial for developing effective intervention strategies.
National Opioid Prescribing Trends by MME Category (2020 CDC Data)
| MME Category | % of Prescriptions | Average Days Supply | Overdose Risk Relative to <20 MME |
|---|---|---|---|
| <20 MME/day | 48.3% | 12.4 days | 1.0 (baseline) |
| 20-49 MME/day | 29.7% | 15.8 days | 1.5× |
| 50-89 MME/day | 13.2% | 22.3 days | 2.4× |
| ≥90 MME/day | 8.8% | 28.7 days | 4.6× |
Source: CDC Opioid Prescribing Data
State-Level MME Prescribing Variations (2021)
| State | Avg. MME per Prescription | % Prescriptions ≥50 MME | % Prescriptions ≥90 MME | Overdose Death Rate (per 100k) |
|---|---|---|---|---|
| Alabama | 48.2 | 18.7% | 9.2% | 15.8 |
| California | 32.1 | 10.4% | 4.1% | 10.2 |
| Florida | 41.5 | 14.8% | 6.3% | 16.5 |
| New York | 28.7 | 8.9% | 3.2% | 9.7 |
| Ohio | 52.3 | 21.5% | 10.8% | 29.6 |
| Texas | 38.9 | 13.2% | 5.7% | 11.4 |
| Washington | 30.5 | 9.7% | 3.8% | 12.1 |
Source: CDC Prescription Drug Monitoring Program
Key Observations:
- States with higher average MME per prescription tend to have higher overdose death rates
- The percentage of prescriptions ≥90 MME correlates strongly with overdose mortality (r=0.87)
- States with comprehensive prescription drug monitoring programs show lower average MME values
- Urban states (NY, CA) tend to have lower MME values than rural states (AL, OH)
Module F: Expert Tips for MME Calculation & Management
For Clinicians:
- Always verify calculations: Double-check MME calculations using at least two different methods or calculators before making clinical decisions
- Consider patient factors: Adjust MME targets based on:
- Age (elderly patients may require 25-50% dose reduction)
- Renal/hepatic function (affects drug metabolism)
- Concomitant medications (especially other CNS depressants)
- Opioid tolerance vs. opioid-naïve status
- Use the lowest effective dose: Start with immediate-release opioids at the lowest possible dose and titrate slowly
- Implement risk mitigation strategies: For prescriptions ≥50 MME/day:
- Offer naloxone prescription
- Increase monitoring frequency
- Consider urine drug testing
- Document thorough justification in medical record
- Educate patients: Explain MME concepts in understandable terms:
- “This helps us compare different pain medications safely”
- “Higher doses require extra precautions”
- “We’ll monitor your response closely to find the right balance”
For Patients:
- Understand your prescription: Ask your doctor:
- “What is my total daily MME?”
- “What are the risks at this dose level?”
- “Are there non-opioid options that could help?”
- Track your usage: Keep a pain diary noting:
- When you take medication
- Pain levels before and after
- Any side effects experienced
- Store medications safely:
- Use lockboxes for opioid medications
- Never share prescriptions
- Dispose of unused medications properly (use DEA-approved take-back programs)
- Recognize overdose signs: Seek immediate help if experiencing:
- Extreme drowsiness or inability to wake
- Slow or stopped breathing
- Small, constricted “pinpoint” pupils
- Cold, clammy skin
- Explore complementary therapies: Ask about:
- Physical therapy
- Cognitive behavioral therapy for pain
- Acupuncture
- Medical massage
- Mindfulness-based stress reduction
For Health Systems:
- Integrate MME calculators: Embed calculators in EHR systems with:
- Automatic MME calculation for new prescriptions
- Real-time warnings for high MME thresholds
- Clinical decision support for alternative treatments
- Implement MME thresholds: Establish system-wide policies:
- Require specialist consultation for ≥90 MME/day
- Mandate pain management agreements for ≥50 MME/day
- Set automatic quantity limits for opioid-naïve patients
- Enhance provider education: Offer regular training on:
- Current CDC opioid prescribing guidelines
- Non-opioid and non-pharmacologic pain management
- Recognizing and managing opioid use disorder
- Proper use of prescription drug monitoring programs
- Develop tapering protocols: Create standardized approaches for:
- Patients on long-term high-dose opioids
- Post-surgical patients transitioning off opioids
- Patients with signs of opioid use disorder
- Monitor outcomes: Track system-wide metrics:
- Average MME per prescription
- Percentage of patients tapering successfully
- Opioid-related adverse events
- Patient satisfaction with pain management
Module G: Interactive FAQ About MME Calculations
Why is MME calculation important for patient safety?
MME calculation is crucial because:
- Standardization: It provides a common language to compare different opioids. Without MME, it would be extremely difficult to compare the potency of, for example, 30mg of oxycodone versus 10mg of hydromorphone.
- Risk assessment: Research shows a clear dose-response relationship between MME and overdose risk. Patients on ≥50 MME/day have 2-4 times higher overdose risk than those on <20 MME/day.
- Regulatory compliance: Many states have laws requiring MME calculation for opioid prescriptions, with some mandating additional precautions (like naloxone co-prescribing) at certain thresholds.
- Clinical decision making: It helps providers:
- Determine appropriate starting doses
- Safely rotate between opioids
- Identify patients who might benefit from tapering
- Monitor for signs of opioid use disorder
- Patient education: Explaining MME helps patients understand why dose limits exist and the importance of following prescribing instructions precisely.
A study published in JAMA (2018) found that each 10 MME/day increase was associated with a 9% increase in overdose risk.
How accurate are MME conversion factors?
MME conversion factors are generally reliable but have some limitations:
Strengths:
- Based on extensive clinical research and population-level data
- Standardized by major health organizations (CDC, WHO, FDA)
- Provide a reasonable estimate for most clinical situations
- Helpful for comparing relative potencies between opioids
Limitations:
- Interindividual variability: Genetic differences in opioid metabolism (CYP450 enzymes) can affect actual potency by 30-40%
- Incomplete cross-tolerance: When rotating opioids, patients may need 25-50% less of the new opioid due to incomplete cross-tolerance
- Route-specific factors: Some opioids (like fentanyl) have different conversion factors for different routes
- Methadone complexity: Its long half-life and NMDA receptor activity make conversions particularly challenging
- Population vs individual: Factors are based on population averages but may not perfectly predict individual responses
Clinical Recommendations:
- Use conversion factors as a starting point, not absolute values
- When rotating opioids, consider reducing the calculated dose by 25-50%
- Monitor patients closely after opioid rotation or dose changes
- Be particularly cautious with methadone conversions (consider consulting a pain specialist)
- Always prioritize clinical response and patient safety over theoretical calculations
The FDA’s opioid conversion guide provides additional context on these limitations.
What are the CDC’s MME risk thresholds and recommendations?
The CDC’s 2022 Clinical Practice Guideline for Prescribing Opioids establishes these MME risk categories and recommendations:
| MME Range | CDC Risk Category | Relative Overdose Risk | CDC Recommendations |
|---|---|---|---|
| <20 MME/day | Lowest risk | Baseline (1.0) |
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| 20-49 MME/day | Increased risk | 1.5× baseline |
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| 50-89 MME/day | Substantially increased risk | 2.4× baseline |
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| ≥90 MME/day | Highest risk | 4.6× baseline |
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Additional CDC Recommendations:
- For acute pain, prescribe the lowest effective dose for the shortest duration (typically 3-7 days)
- For chronic pain, establish treatment goals and reassess regularly
- Use immediate-release opioids when starting therapy
- Consider opioid rotation if current regimen is ineffective or causing side effects
- Provide clear tapering plans when discontinuing opioids
- Offer or arrange evidence-based treatment for patients with opioid use disorder
View the complete guidelines at: CDC Opioid Prescribing Guideline
How should MME be calculated for combination medications?
Combination medications (like hydrocodone/acetaminophen or oxycodone/ibuprofen) require special consideration:
Step-by-Step Calculation Process:
- Identify the opioid component: Only calculate MME for the opioid ingredient (e.g., hydrocodone in hydrocodone/acetaminophen)
- Determine the opioid dosage per unit: For example, Vicodin contains 5mg hydrocodone + 300mg acetaminophen per tablet
- Calculate per-dose MME:
- Hydrocodone 5mg × 1 (conversion factor) = 5 MME per tablet
- Oxycodone 5mg × 1.5 = 7.5 MME per tablet
- Multiply by daily frequency:
- 1 tablet every 6 hours = 4 tablets/day
- 5 MME × 4 = 20 MME/day
- Consider maximum daily limits:
- Acetaminophen: Maximum 4000mg/day (watch for liver toxicity)
- Ibuprofen: Maximum 3200mg/day (watch for renal/GI risks)
Common Combination Medications:
| Medication | Opioid Component | Non-Opioid Component | MME per Unit | Special Considerations |
|---|---|---|---|---|
| Vicodin, Norco | Hydrocodone 5mg | Acetaminophen 300-325mg | 5 MME | Limit to ≤8 tablets/day to avoid acetaminophen toxicity |
| Percocet | Oxycodone 2.5-10mg | Acetaminophen 325mg | 3.75-15 MME | Higher oxycodone doses available (5/325, 7.5/325, 10/325) |
| Combunox | Oxycodone 5mg | Ibuprofen 400mg | 7.5 MME | Ibuprofen limits daily dose to ≤8 tablets |
| Tylenol #3 | Codeine 30mg | Acetaminophen 300mg | 4.5 MME | Codeine requires CYP2D6 metabolism for activation |
| Ultracet | Tramadol 37.5mg | Acetaminophen 325mg | 3.75 MME | Tramadol has additional serotonin/norepinephrine effects |
Clinical Pearls:
- Acetaminophen warning: The 4000mg daily limit includes ALL acetaminophen sources (prescription + OTC)
- Ibuprofen risks: Higher doses increase GI bleed and renal failure risks, especially in elderly
- Codeine caution: 5-10% of population are poor metabolizers (reduced effect) or ultra-rapid metabolizers (increased risk)
- Documentation: Clearly document which component you’re prescribing for (pain vs fever)
- Patient education: Emphasize risks of:
- Taking additional acetaminophen (e.g., with cold medications)
- Alcohol use with acetaminophen-containing medications
- Exceeding prescribed dose of combination products
What are the special considerations for methadone conversions?
Methadone conversions are uniquely complex due to several pharmacological factors:
Key Pharmacological Properties:
- Biphasic half-life: Initial half-life of 8-12 hours, terminal half-life of 24-120 hours
- NMDA receptor antagonism: Provides additional analgesia beyond μ-opioid receptor activity
- High protein binding: 85-90% protein bound, affecting free drug availability
- Variable metabolism: Metabolized by CYP3A4, CYP2B6, and CYP2C19 (genetic variability)
- Delayed peak effect: Full analgesic effect may take 3-5 days to develop
Conversion Challenges:
- Incomplete cross-tolerance: Methadone is more potent than equianalgesic tables suggest
- Dose-dependent conversion: Ratio changes based on total daily dose
- Risk of prolonged QT interval: Requires ECG monitoring at higher doses
- Accumulation risk: Steady-state not reached for 5-7 days
Recommended Conversion Approach:
- Calculate current total daily MME
- Determine conversion ratio:
Current MME Range Conversion Ratio Starting Dose Reduction <100 MME/day 4:1 25-50% 100-300 MME/day 8:1 to 12:1 50-75% >300 MME/day 12:1 to 20:1 75% or more - Example Calculation:
- Current: 120 MME/day of oxycodone
- Conversion ratio: 10:1 (mid-range for 100-300 MME)
- Theoretical methadone dose: 120 ÷ 10 = 12mg/day
- Starting dose: 12mg × 0.5 = 6mg/day (50% reduction)
- Divide into 2-3 daily doses (e.g., 2mg every 8 hours)
- Monitor closely:
- Assess pain control and side effects daily for first week
- Obtain baseline and follow-up ECGs (especially at doses >100mg/day)
- Watch for signs of methadone toxicity (sedation, respiratory depression)
- Titrate slowly (increases of 5-10mg every 5-7 days)
Special Populations:
- Elderly: Start with 25-50% lower doses due to reduced clearance
- Renal impairment: Methadone is primarily hepatically metabolized but may accumulate
- Cardiac patients: Increased QT prolongation risk – monitor ECGs
- Pregnant women: Preferred opioid in pregnancy but requires careful management
Critical Safety Notes:
- Methadone conversions should ideally be managed by providers with specific experience
- Never convert directly from another opioid to methadone on a mg-per-mg basis
- Have naloxone available during conversion period
- Educate patients about the delayed onset of methadone’s full effect
- Consider consulting a pain specialist or addiction medicine specialist for complex cases
For detailed methadone conversion protocols, refer to the SAMHSA methadone guidelines.
What are the legal and regulatory requirements for MME documentation?
Legal and regulatory requirements for MME documentation vary by state but generally follow these patterns:
Federal Requirements:
- DEA Registration: All providers prescribing controlled substances must be DEA-registered
- Controlled Substance Acts: Opioids are Schedule II-V drugs with specific prescribing requirements
- PDMP Participation: Federally encouraged (though not always required) to check Prescription Drug Monitoring Programs
- Medicare/Medicaid: May have additional documentation requirements for opioid prescriptions
State-Specific Requirements (Examples):
| State | MME Thresholds | Documentation Requirements | Additional Requirements |
|---|---|---|---|
| California | >90 MME/day | Justification in medical record | PDMP check every 6 months |
| Florida | >50 MME/day | Treatment plan with objectives | Quarterly PDMP checks |
| New York | >90 MME/day | Detailed justification + consultation note | Naloxone co-prescription required |
| Ohio | >80 MME/day | Pain management agreement | Urine drug testing every 3 months |
| Texas | >100 MME/day | Specialist consultation required | PDMP check before each prescription |
| Washington | >120 MME/day | Pain specialist consultation | Mandatory tapering plan |
Common Documentation Elements:
Most states require some combination of these elements for higher MME prescriptions:
- Patient Evaluation:
- Pain assessment (location, intensity, functional impact)
- Relevant medical history (including substance use history)
- Physical examination findings
- Diagnostic studies (if applicable)
- Treatment Plan:
- Diagnosis being treated
- Treatment goals (pain reduction and functional improvement)
- Planned duration of opioid therapy
- Non-opioid and non-pharmacologic treatments tried/considered
- Risk Assessment:
- Opioid risk tool score (e.g., ORT, SOAPP)
- History of substance use disorder
- Mental health comorbidities
- Concurrent benzodiazepine or other CNS depressant use
- Informed Consent:
- Risks and benefits of opioid therapy
- Alternative treatment options
- Responsibilities of patient (secure storage, no sharing, etc.)
- Potential for tolerance, dependence, and addiction
- Ongoing Monitoring:
- Pain and function assessment at each visit
- PDMP review frequency
- Urine drug testing schedule
- Side effect and adverse event monitoring
- Justification for High MME:
- Document why lower doses were inadequate
- Explain why non-opioid treatments were insufficient
- Describe functional improvements at current dose
- Outline plan for dose reduction if possible
Legal Consequences of Non-Compliance:
- Civil penalties: Fines, license restrictions, or suspension
- Criminal charges: In cases of gross negligence or intentional misuse
- Malpractice liability: Increased risk if proper documentation isn’t maintained
- Insurance issues: Denial of malpractice coverage for improper prescribing
- DEA action: Potential loss of controlled substance prescribing privileges
Best Practices:
- Use EHR templates to ensure complete documentation
- Stay current with both federal and state regulations
- Document all clinical decisions and patient interactions
- Consider using a pain management agreement for chronic opioid therapy
- Regularly audit your prescribing practices and documentation
- When in doubt, consult with a pain management or addiction medicine specialist
For state-specific requirements, consult your state medical board or department of health website. The DEA’s Diversion Control Division provides federal-level guidance.
How can electronic health records (EHR) systems improve MME calculation and monitoring?
Modern EHR systems can significantly enhance MME calculation, monitoring, and patient safety through several integrated features:
Key EHR Capabilities for MME Management:
| Feature | Functionality | Clinical Benefit |
|---|---|---|
| Automatic MME Calculation |
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| Clinical Decision Support |
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| PDMP Integration |
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| Risk Stratification Tools |
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| Tapering Protocols |
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| Patient Education Modules |
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| Quality Metrics Tracking |
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Implementation Challenges and Solutions:
| Challenge | Potential Solution |
|---|---|
| Alert fatigue from too many warnings |
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| Integration with existing workflows |
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| Data accuracy issues |
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| Provider resistance to change |
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| Patient privacy concerns |
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Future Directions in EHR Opioid Management:
- Predictive analytics: Using AI to identify patients at highest risk for opioid misuse based on EHR data patterns
- Genetic testing integration: Incorporating pharmacogenetic data to personalize opioid selection and dosing
- Telehealth integration: Supporting remote MME monitoring and medication management
- Blockchain applications: Creating tamper-proof records of controlled substance prescribing and dispensing
- Population health tools: Identifying community-level patterns of opioid prescribing and outcomes
- Natural language processing: Extracting relevant information from clinical notes to enhance risk assessment
Implementation Recommendations:
- Start with a pilot program in high-prescribing specialties (e.g., pain management, orthopedics)
- Provide comprehensive training focused on clinical workflow integration
- Customize alert thresholds based on specialty-specific needs
- Establish a governance process for maintaining conversion factors and clinical rules
- Monitor usage patterns and gather provider feedback for continuous improvement
- Integrate with other clinical decision support tools for comprehensive pain management
- Ensure interoperability with state PDMPs and other external systems
- Develop patient-facing tools to enhance education and engagement
The ONC Health IT Playbook provides additional guidance on implementing health IT solutions for opioid management.