Electronic Medication Event Monitoring

ELECTRONIC MEDICATION EVENT MONITORING

The technological advance that has lifted the topic of patient adherence out of its longstanding methodological morass has been the microelectronic revolution, which opened the door to the possibility of objectively compiling ambulatory patients’ drug dosing histories through the integration of time-stamping/data storing microcircuitry into standard pharmaceutical packages. The first commercially available electron-ically monitored drug package, the MEMS^® Moni-tor, appeared in the scientific products marketplace in 1989. This product inferentially compiled drug intake by detecting, time-stamping and storing time and dates of successive entries into the package in which prescribed drug is dispensed. Of course, the time of entry into a drug package is an indirect, or surrogate, measure of drug actually taken. Recently this surrogate measure was validated by demonstrat-ing close correspondence between directly measured concentrations of drug in plasma at specific times, and, based on electronically compiled package-entry times, the pharmacokinetically projected concentra-tion of drug in plasma at the same time (Vrijens et al., 2005b).

Prior to this validation, electronic monitoring had already been in use between 1989 and 2005, giving rise to approximately 250 peer-reviewed, published studies in which electronically monitored drug dosing times were used as a measure of drug intake. These studies provide a diverse array of demonstrations of the essential practicality of using the MEMS Moni-tors in clinical investigation, together with the often-surprising departures of reality from conventional assumptions about drug exposure in various treatment and research situations involving ambulatory patients.

It is also noteworthy that the vast majority of these studies were conceived, performed, analysed and reported by investigators whose only involve-ment with the manufacturer of MEMS Monitors was their purchase of the Monitors and receipt of customer service advice regarding details of product use. Some users of MEMS have opted to have their data anal-ysed at the recently established AARDEX Statistical Research Centre in Visé, Belgium, done on a fee for service basis.

Many commentators or reviewers of the field of patient adherence have described the MEMS Moni-tors as ‘expensive’ (see, e.g., Osterberg and Blaschke, 2005), leaving it to the reader to infer: (a) the costs of the various pre-electronic techniques of compiling drug dosing histories in ambulatory patients; (b) the values of having reliable data on ambulatory patients’ drug dosing histories.