Perioperative drug pharmacokinetics in patients with obesity

PURPOSE OF REVIEW: Obesity-related changes in body composition and organ function modify drug pharmacokinetics and pharmacodynamics, challenging standard dosing strategies. This review summarizes recent data on perioperative pharmacokinetics in patients with obesity and discusses implications for anesthetic drug dosing. RECENT FINDINGS: Recent data confirm that excess adiposity induces drug-specific alterations in distribution, hepatic clearance, and renal elimination. Lipophilic agents exhibit increased volumes of distribution with risk of accumulation, whereas hydrophilic drugs are prone to excessive plasma exposure when dosed according to total body weight. Recent clinical and pharmacokinetic studies have generated dosing data for several perioperative agents in patients with obesity, including remimazolam, ciprofol, and intravenous lidocaine. In contrast, pharmacokinetic evidence remains limited for other commonly used drugs, notably ketamine, magnesium sulfate, and dexamethasone. The incidence of sleep apnea is high in obese patients and restrictive use or avoiding of opioids is advised. Studies evaluating multimodal and opioid-free anesthesia in patients with obesity report heterogeneous outcomes, reflecting uncertainty in dosing strategies and comparator regimens. SUMMARY: Perioperative drug dosing in patients with obesity requires an individualized approach based on pharmacokinetic principles and clinical titration. Further obesity-specific pharmacokinetic and pharmacodynamic studies are needed to support safe and effective management in this population.