The Medication Quantification Scale (MQS) is an instrument with potential clinical and research applications for quantifying medication regimen use in chronic pain populations. The MQS was developed in 1992 and updated in 1998 (MQS II) as a tool to co-quantify 3 relevant aspects of medications prescribed for chronic nonmalignant pain: drug class, dosage, and detriment (risk). This 2003 version (MQS III) is the third iteration of the scale, featuring new detriment weights determined by surveying all physician members of the American Pain Society in the United States via mail. A total of 248 physicians (18%) responded with their opinion as to the detriment of 22 mechanistically distinct medication classes. Overall, the physician ratings of detriment weight were relatively consistent (alpha = .84). The increased number of survey responses encompassed a wide range of disciplines, thus reducing discipline bias and introducing several important changes to MQS scoring. Some medication classes previously rated with low detriment weights (eg, nonsteroidal anti-inflammatory drugs) increased in detriment weight (from 2 to 3.4), whereas other classes previously given high weights (eg, "strong" opioids) received lower detriment ratings (from 5 to 3.4) in this survey. The MQS III must now be validated in clinical and research applications.
Perspective: The MQS is a tool to objectively quantify pain. It computes a single numeric value for a patient's pain medication profile. This number can be used by both clinicians and researchers to track pain levels through a treatment course or research study.