Therapeutic drug monitoring to adjust dosing in morbid obesity – a new use for an old methodology

The phenomena of hunger and need at one end of the spectrum and obesity and plenty on the other is an anomaly of the 21 st century, likely to be due to a combination of distributive inequities in food, social justice, access to education and other socio‐economic factors. Both are major problems worldwide, although obesity has more media coverage due to the exponentially increasing incidence and the huge social and economic burden this is placing on Western society. For example, prevalence rates of obesity are currently exceeding 30% of adults in the USA with direct morbidity and mortality complications, in addition to the additional obesity‐related health problems and death. Obesity is also rising in children. Obese people are thus a sizable group, and as with those with altered renal or liver function, require specific consideration with respect to the appropriate dosing of medications. However guidelines for how to do this in obesity are not currently available, due to the paucity of literature and regulatory rules for new medications which usually only request the demonstration of average population effectiveness. We believe it is timely for regulatory agencies worldwide to mandate studies involving consideration of body size, particularly obesity, in approving new medications across the therapeutic spectrum. This will drive the pharmaceutical industry to consider these groups in studies and will encourage investigator‐initiated research using therapeutic drug monitoring (TDM), target concentration therapy (TCI) and pharmacogenetic (PGx) studies to optimize drug dosing.