Pharmacokinetic considerations in the obese

The steady rise in obesity observed in the recent years, coupled with its associated co-morbidities, suggests that clinicians will encounter obese patients with increasing frequency in their daily practice. Unfortunately, obese subjects are often excluded from clinical trials during the drug development process. Hence, the appropriate dose for obese patients is most often inferred from normal-weight subjects. Pharmacokinetic and pharmacodynamic variations induced by obesity are numerous and with profound clinical implications, particularly in anaesthesia and intensive care. This review provides a pragmatic approach to the pharmacokinetic considerations that should guide drug administration. We hereby offer a systematic approach to dosing scalars, followed by an analysis of the factors affecting pharmacokinetics in obesity, and provide a detailed discussion on the single most commonly used pharmacological agents in anaesthesia.