Standardizing research methods for opioid dose comparison: the NIH HEAL morphine milligram equivalent calculator.

We developed the National Institutes of Health helping to end addiction long-term initiative morphine milligram equivalent (MME) calculator to standardize MME calculations across pain research studies, addressing a critical barrier to effective research synthesis and meta-analysis. The tool provides evidence-based mapping factors for 29 opioids through a research electronic data capture-based calculator and companion Web site (research-mme.wakehealth.