Do Obese People Need More Drugs?Thursday, March 4, 2010
Of course, obesity is associated with a wide range of health problems like high blood pressure, diabetes, arthritis, or reflux disease, all of which may all require pharmacological treatment. But this is not what this post is about.
Rather, this post is actually about the question whether or not larger patients need higher doses of medications to have an optimal treatment effect.
This topic was recently discussed by Matthew Falagas and Drosos Karageorgopoulos in a Lancet article that specifically addresses the issue of dose adjustments for antimicrobial agents in larger patients.
As the authors point out, body size is routinely considered in the optimization of drug therapy in oncology, anaesthetics and pediatrics. However, there remains a paucity of data on the optimal dosing of pharmacological agents for most of the drugs we use in clinical practice.
Thus, although regulatory agencies regularly demand special pharmacokinetic studies in children, elderly prople and patients with renal or hepatic impairment, no such studies are demanded for obese or even severely obese patients.
Requiring such studies would at least make theoretical sense as, conceivably, obesity can affect drug absorption, distribution, metabolism and clearance. Furthermore, it is obvious that body composition can particularly affect the disposition of lipophilic compounds. Obese patients are also likely to have comorbiditiesthat can affect these parameters (e.g. fatty liver disease) and are much more likely to be on multiple medications that can make drug-drug interactions problematic.
In short, as pointed out by Falgas and Karageorgopoulos the one-size-fits-all strategy for antimicrobial agents (and other drugs?) may well be outdated and require much more consideration than has been given to this issue in the past.