Gypsy Girl Mosaic

Drug Labeling That Fails People with Obesity

It is hard to believe. But a new commentary in Health Affairs Forefront tells us once again that drug labeling fails to assure safe and effective use for many important drugs by people with obesity. These are drugs for conditions other than obesity. But people with obesity may represent half or more of the people who take them.

Authors Christina Chow, David Greenblatt, and William Dietz explain:

“Obesity affects the way drugs behave in the body. Yet, our regulatory systems ignore this fact entirely.

“Currently, there are no requirements to evaluate how drugs act in people with obesity, and it is unknown whether all drugs are safe and effective for people with obesity.

“Regulators and policy makers can and should act now to address those failures, reduce uncertainty, protect patients, and improve health.”

A Large Population at Risk

This is the nub of the problem. Regulators at FDA and many pharmaceutical companies are leaving a large segment of the population at risk by not requiring that products be tested and labeled for safe and effective use in roughly half of the population.

For some drugs, it can be more than half of a drug’s users. For example, Rexulti (brexpiprazole) is marketed by Otsuka for schizophrenia and major depression. The prevalence of obesity in schizophrenia is 59% by one recent estimate. And yet, persons with obesity were largely excluded from clinical trials that led to the approval for Rexulti. Pharmacokinetic studies reveal that the directions for use will virtually assure that people with severe obesity will never reach therapeutic levels for this important drug. It is a loss for everyone.


Why does this happen? The reason is simple. Researchers get cleaner data and a clearer picture of safety and effectiveness if patients with a lot of other problems don’t muck it up with complications from their other problems. Who are the patients that might have a lot of other problems? People living with obesity. So by excluding patients with conditions that are common in people with obesity, drug companies can wind up excluding people with obesity from their clinical trial. Chow, Greenblatt, and Dietz describe the situation:

“Pharmaceutical companies are not required to include people with obesity in clinical studies, and the FDA has recognized that people with obesity are often excluded in an effort to reduce the variability in the effects of a drug.”

Everything is tidier when researchers leave out people with obesity from their studies. The only problem is that the drug labeling that results does not tell doctors how to use these drugs safely and effectively in half of the population or more – people living with obesity.

This is a mistake that FDA and pharmaceutical companies should fix without delay.

Click here for the new article from Health Affairs and here for perspective on size diversity in clinical trials.

Gypsy Girl Mosaic from the Zeugma Mosaic Museum, photograph by Nevit Dilmen, licensed under CC BY-SA 3.0

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August 31, 2023