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The Opioid Conversion Calculator (MME) converts any opioid prescription to Morphine Milligram Equivalents (MME), the standardized measure used by the CDC, CMS, and state Prescription Drug Monitoring Programs to assess opioid exposure and overdose risk. Understanding MME is critical in the context of the ongoing opioid epidemic.
The United States faces an unprecedented opioid crisis, with over 80,000 opioid-related overdose deaths annually. In response, the CDC Clinical Practice Guideline for Prescribing Opioids (2022) emphasizes careful dose assessment using MME as the universal metric. MME allows direct comparison between different opioid medications, regardless of potency, formulation, or dosing frequency.
Each opioid has a unique conversion factor that reflects its potency relative to oral morphine. Oral morphine is the reference standard with a factor of 1. Oxycodone is 1.5 times more potent (factor 1.5), meaning 10 mg of oxycodone equals 15 MME. Hydromorphone is 4 times more potent (factor 4), so 10 mg equals 40 MME. Fentanyl patches use a unique conversion where each mcg/hr of the transdermal patch equals 2.4 MME/day (per CDC 2022, using the factor of 75 for the mcg/hr value).
The CDC identifies key MME thresholds for risk assessment: below 50 MME/day is considered lower risk; 50-89 MME/day warrants careful reassessment of pain management strategies and consideration of dose reduction; and 90 MME/day or above significantly increases overdose risk and should prompt serious reconsideration of the opioid regimen, with naloxone co-prescribing strongly recommended.
Important limitations exist for MME calculations. Methadone has variable conversion ratios depending on the total daily dose, making simple multiplication potentially dangerous. Buprenorphine is a partial agonist with a ceiling effect and is typically excluded from MME calculations when used for opioid use disorder treatment. Transdermal and extended-release formulations have different pharmacokinetics than immediate-release products.
This calculator uses CDC-recommended conversion factors and provides the daily MME with a risk category to support informed clinical decision-making and regulatory compliance.
The MME calculation uses standardized conversion factors:
Conversion factors are from the CDC 2022 guideline. For fentanyl patches, the dose is in mcg/hr and the factor converts directly to daily MME. Methadone conversion uses the factor for doses ≤20 mg/day; higher doses require clinical judgment.
The Daily MME is the primary measure for assessing opioid exposure risk. A Risk Category of 1 (under 50 MME) indicates lower overdose risk. Category 2 (50-89 MME) warrants reassessment and naloxone discussion. Category 3 (90+ MME) indicates significantly elevated risk — the CDC recommends avoiding or carefully justifying doses at or above this threshold. These are guidelines, not rigid rules; individual patient circumstances always apply. This calculator does not replace clinical judgment or account for tolerance, interacting medications, or comorbidities.
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Oxycodone 10 mg four times daily = 40 mg/day × 1.5 = 60 MME/day. This falls in the moderate risk category (50-89 MME).
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Morphine 15 mg three times daily = 45 MME/day. Below the 50 MME threshold — lower risk category.
Morphine Milligram Equivalents (MME) is a standardized value that converts any opioid dose to the equivalent dose of oral morphine. It allows direct comparison of different opioids regardless of the specific drug, formulation, or potency.
CDC analysis showed that patients receiving 90+ MME/day had significantly higher overdose rates compared to those on lower doses. The risk increases progressively, with 90 MME representing a threshold where the overdose risk roughly doubles compared to under 20 MME.
Conversion factors represent potency relative to oral morphine: Codeine 0.15, Tramadol 0.1, Hydrocodone 0.25 (per some guidelines 1.0), Morphine 1.0, Oxycodone 1.5, Hydromorphone 4.0, Methadone variable (3-12 depending on dose), Fentanyl patch 75 per mcg/hr.
This calculator computes MME for risk assessment, not equianalgesic dosing for opioid rotation. When switching opioids, clinicians typically reduce the calculated equivalent dose by 25-50% to account for incomplete cross-tolerance, then titrate to effect.
The CDC recommends discussing naloxone when prescribing opioids at 50+ MME/day, when opioids are combined with benzodiazepines, or when patients have a history of overdose, substance use disorder, or other risk factors for opioid-related harm.
Methadone has variable conversion ratios: at low doses (≤20 mg/day) the factor is approximately 3-4, but at higher doses it increases to 8-12 due to methadone's unique pharmacology. This makes methadone conversions particularly dangerous without specialist guidance.
The 2022 CDC guideline is a clinical practice guideline, not a regulation. However, many states have incorporated MME thresholds into laws or regulations. Insurance companies and pharmacies also use MME limits for utilization management and prior authorization requirements.
When a patient takes multiple opioids, calculate the MME for each separately, then sum them. For example, oxycodone 30 MME + morphine 20 MME = 50 MME total daily exposure. This total determines the risk category.
Fentanyl patches are rated in mcg/hr. A 25 mcg/hr patch delivers approximately 60 MME/day. The conversion factor of 75 is applied to the mcg/hr value: 25 × 75 ÷ 24 ≈ 78 MME/day (different sources vary; this calculator uses the CDC factor directly as daily equivalent).
Tapering means gradually reducing the opioid dose, typically by 5-10% per week or per month. It is recommended when risks outweigh benefits, the patient requests it, pain has resolved, or the patient shows signs of misuse. Rapid tapering can cause withdrawal and should be avoided.
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