Severe obesity complicates ICU drug dosing, review concludes

A narrative review concludes that medication dosing in critically ill patients with severe or extreme obesity requires individual assessment because standard doses in product labels and tertiary references often do not account for obesity-related pharmacokinetic and pharmacodynamic variability. The authors warn that this mismatch can contribute to treatment failure or adverse effects, although the review is not based on a new clinical trial and the underlying ICU-specific evidence remains limited. The publication focuses on intensive care unit patients with extreme obesity, a group that has become more common in critical care and presents a distinct dosing challenge.

To assemble its guidance, the authors searched the literature for articles addressing the pharmacokinetics or pharmacodynamics of medications in obese patients. They included literature describing general treatment principles and medication-specific assessments, then searched bibliographies for additional publications. The resulting recommendations synthesize existing evidence rather than report outcomes from a prospectively tested dosing protocol.

At the center of the proposed approach is the question of which patient weight to use for weight-based calculations and which dose to select for fixed regimens. The review notes that these changes may hinder attainment of pharmacodynamic targets. Its practical framework therefore links the selected weight or dose to the goal for the individual patient, requiring clinicians to assess pharmacokinetic variability and whether the intended pharmacodynamic goal can be achieved.

Several limitations limit the strength and generalizability of the evidence. The authors identify the small number of patients with more extreme forms of obesity, a lack of clinical-outcome measurements, and the few studies conducted specifically in intensive care. These constraints mean the review should be understood as guidance grounded in the available literature, not as proof that one dosing strategy improves outcomes across all critically ill patients with obesity.

Medication-specific recommendations are provided for selected ICU medicines, but the evidence supporting them should be considered in light of these limitations. The review’s overall conclusion is that drug dosing in critically ill patients with extreme obesity should be individualized by evaluating pharmacokinetic variability and determining whether the regimen can achieve the relevant pharmacodynamic goal. Selecting the correct weight for weight-based calculations or the correct dose for a fixed regimen is described as paramount to that process.

The authors also say consultation with a clinical pharmacist may be beneficial when evaluating complex regimens. These recommendations address how clinicians can structure dosing decisions, but the available evidence does not establish that the framework reduces mortality, treatment failure, adverse effects, or length of ICU stay. Instead, it offers a practical response to a population in which standard dosing instructions may not adequately reflect drug distribution, clearance, and treatment goals.

Subject of Research: Individualized medication dosing for critically ill patients with severe obesity in intensive care.

Article Title: Principles of drug dosing for obese patients in the intensive care unit

Article References: Barletta, J. F., & Erstad, B. L. (2026). Principles of drug dosing for obese patients in the intensive care unit. Intensive Care Medicine. https://doi.org/10.1007/s00134-026-08628-7

Image Credits: AI Generated

DOI: 10.1007/s00134-026-08628-7

Keywords: severe obesity, ICU medication dosing, pharmacokinetics, pharmacodynamics, drug clearance, volume of distribution, weight-based dosing, clinical pharmacy, intensive care, medication safety, Principles, drug