10 drugs that need dose adjustment in obesity

There's more to it than total body weight
fat paper people

Estimating the optimal drug dose for obese patients can be difficult, say pharmacologists.

That’s because simply basing maintenance doses on total body weight is risky, says Associate Professor Michael Barras from the University of Queensland.

Instead, individualised dosing based on the patient’s lean body weight is recommended.

“Using total body weight assumes that the pharmacokinetics of the drug are linearly scalable from normal-weight patients to those who are obese,” writes Dr Barras in Australian Prescriber.

“This is inaccurate," he says.

For example, it cannot be assumed that a 150kg patient eliminates a drug twice as fast as a 75kg patient and therefore needs double the dose.

“Drug clearance is greater in obesity and correlates with lean body weight,” Dr Barras says.

Drugs that require dose adjustment in obesity include: